Marathon Petroleum (MPC) 10-K 24 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2016	Feb. 13, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Trading Symbol	MPC
Entity Registrant Name	Marathon Petroleum Corp
Entity Central Index Key	1,510,295
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		527,782,929
Entity Public Float			$ 20

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues and other income:
Sales and other operating revenues (including consumer excise taxes)	$ 63,339	$ 72,051	$ 97,817
Income (loss) from equity method investments	(185)	88	153
Net gain on disposal of assets	32	7	21
Other income	178	112	111
Total revenues and other income	63,364	72,258	98,102
Costs and expenses:
Cost of revenues (excludes items below)	49,170	55,583	83,770
Purchases from related parties	509	308	505
Inventory market valuation adjustment	(370)	370	0
Consumer excise taxes	7,506	7,692	6,685
Impairment expense	130	144	0
Depreciation and amortization	2,001	1,502	1,326
Selling, general and administrative expenses	1,605	1,576	1,375
Other taxes	435	391	390
Total costs and expenses	60,986	67,566	94,051
Income from operations	2,378	4,692	4,051
Net interest and other financial income (costs)	(556)	(318)	(216)
Income before income taxes	1,822	4,374	3,835
Provision for income taxes	609	1,506	1,280
Net income	1,213	2,868	2,555
Less net income (loss) attributable to:
Redeemable noncontrolling interest	41	0	0
Noncontrolling interests	(2)	16	31
Net income attributable to MPC	$ 1,174	$ 2,852	$ 2,524
Basic:
Net income attributable to MPC per share	$ 2.22	$ 5.29	$ 4.42
Weighted average shares outstanding (in shares)	528	538	570
Diluted:
Net income attributable to MPC per share	$ 2.21	$ 5.26	$ 4.39
Weighted average shares outstanding (in shares)	530	542	574
Dividends paid (in USD per share)	$ 1.36	$ 1.14	$ 0.92

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 1,213	$ 2,868	$ 2,555
Defined benefit postretirement and post-employment plans:
Actuarial changes, net of tax of $69, $21 and ($47)	115	34	(78)
Prior service costs, net of tax of ($18), ($24) and ($19)	(31)	(39)	(31)
Other comprehensive income (loss)	84	(5)	(109)
Comprehensive income	1,297	2,863	2,446
Less comprehensive income (loss) attributable to:
Redeemable noncontrolling interest	41	0	0
Noncontrolling interests	(2)	16	31
Comprehensive income attributable to MPC	$ 1,258	$ 2,847	$ 2,415

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Actuarial changes, tax	$ 69	$ 21	$ (47)
Prior service costs, tax	$ (18)	$ (24)	$ (19)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents (MPLX: $234 and $43, respectively)	$ 887	$ 1,127
Receivables, less allowance for doubtful accounts of $12 and $12 (MPLX: $302 and $257, respectively)	3,617	2,927
Inventories (MPLX: $54 and $51, respectively)	5,656	5,225
Other current assets (MPLX: $33 and $50, respectively)	241	192
Total current assets	10,401	9,471
Equity method investments (MPLX: $2,467 and $2,458, respectively)	3,827	3,622
Property, plant and equipment, net (MPLX: $10,730 and $9,997, respectively)	25,765	25,164
Goodwill (MPLX: $2,199 and $2,570, respectively)	3,587	4,019
Other noncurrent assets (MPLX: $506 and $478, respectively)	833	839
Total assets	44,413	43,115
Current liabilities:
Accounts payable (MPLX: $506 and $449, respectively)	5,593	4,743
Payroll and benefits payable (MPLX: $1 and $18, respectively)	530	503
Consumer excise taxes payable (MPLX: $2 and $1, respectively)	464	460
Accrued taxes (MPLX: $31 and $26, respectively)	153	184
Debt due within one year (MPLX: $1 and $1, respectively)	28	29
Other current liabilities (MPLX: $78 and $65, respectively)	378	426
Total current liabilities	7,146	6,345
Long-term debt (MPLX: $4,422 and $5,255, respectively)	10,544	11,896
Deferred income taxes (MPLX: $5 and $378, respectively)	3,861	3,285
Defined benefit postretirement plan obligations	1,055	1,179
Deferred credits and other liabilities (MPLX: $181 and $170, respectively)	604	735
Total liabilities	23,210	23,440
Commitments and contingencies (see Note 25)
Redeemable noncontrolling interest	1,000	0
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 – 731 million and 729 million shares (par value 0.01 per share, 1 billion shares authorized)	7	7
Held in treasury, at cost – 203 million and 198 million shares	(7,482)	(7,275)
Additional paid-in capital	11,060	11,071
Retained earnings	10,206	9,752
Accumulated other comprehensive loss	(234)	(318)
Total MPC stockholders’ equity	13,557	13,237
Noncontrolling interests	6,646	6,438
Total equity	20,203	19,675
Total liabilities, redeemable noncontrolling interest and equity	$ 44,413	$ 43,115

Consolidated MPLX Balance Sheet

Consolidated MPLX Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 887	$ 1,127
Receivables, less allowance for doubtful accounts	3,617	2,927
Inventories	5,656	5,225
Other current assets	241	192
Equity method investments	3,827	3,622
Property, plant and equipment, net	25,765	25,164
Goodwill	3,587	4,019
Other noncurrent assets	833	839
Liabilities
Accounts payable	5,593	4,743
Payroll and benefits payable	530	503
Consumer excise taxes payable	464	460
Accrued taxes	153	184
Debt due within one year	28	29
Other current liabilities	378	426
Total long-term debt due after one year	10,544	11,896
Defined benefit postretirement plan obligations	1,055	1,179
Deferred credits and other liabilities	604	735
MPLX LP
Assets
Cash and cash equivalents	234	43
Receivables, less allowance for doubtful accounts	302	257
Inventories	54	51
Other current assets	33	50
Equity method investments	2,467	2,458
Property, plant and equipment, net	10,730	9,997
Goodwill	2,199	2,570
Other noncurrent assets	506	478
Liabilities
Accounts payable	506	449
Payroll and benefits payable	1	18
Consumer excise taxes payable	2	1
Accrued taxes	31	26
Debt due within one year	1	1
Other current liabilities	78	65
Total long-term debt due after one year	4,422	5,255
Deferred income taxes	5	378
Defined benefit postretirement plan obligations	0	0
Deferred credits and other liabilities	$ 181	$ 170

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 12	$ 12
Preferred stock:
Shares issued	0	0
Shares outstanding	0	0
Par value	$ 0.01
Shares authorized	30,000,000
Common stock:
Shares issued	731,000,000	729,000,000
Par value	$ 0.01
Shares authorized	1,000,000,000
Treasury stock	(203,000,000)	(198,000,000)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net income	$ 1,213	$ 2,868	$ 2,555
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred financing costs and debt discount	61	16	27
Impairment expense	130	144	0
Depreciation and amortization	2,001	1,502	1,326
Inventory market valuation adjustment	(370)	370	0
Pension and other postretirement benefits, net	9	80	151
Deferred income taxes	394	134	(242)
Net gain on disposal of assets	(32)	(7)	(21)
(Income) loss from equity method investments	185	(88)	(153)
Distributions from equity method investments	291	113	170
Changes in the fair value of derivative instruments	(41)	4	(3)
Changes in:
Current receivables	(674)	1,292	1,642
Inventories	(70)	80	(786)
Current accounts payable and accrued liabilities	985	(2,400)	(1,547)
All other, net	(96)	(47)	(9)
Net cash provided by operating activities	3,986	4,061	3,110
Investing activities:
Additions to property, plant and equipment	(2,892)	(1,998)	(1,480)
Acquisitions, net of cash acquired	0	(1,218)	(2,821)
Disposal of assets	101	21	27
Investments – acquisitions, loans and contributions	(288)	(331)	(413)
Investments—redemptions, repayments and return of capital	26	4	9
All other, net	112	81	135
Net cash used in investing activities	(2,941)	(3,441)	(4,543)
Financing activities:
Commercial paper – issued	1,263	0	0
Commercial paper - repayments	(1,263)	0	0
Long-term debt – borrowings	864	2,993	3,793
Long-term debt – repayments	(2,269)	(2,226)	(548)
Debt issuance costs	(11)	(21)	(22)
Issuance of common stock	11	33	26
Common stock repurchased	(197)	(965)	(2,131)
Dividends paid	(719)	(613)	(524)
Issuance of MPLX LP common units	776	0	221
Issuance of MPLX LP redeemable preferred units	984	0	0
Distributions to noncontrolling interests	(542)	(40)	(27)
Contingent consideration payment	(164)	(175)	(172)
All other, net	(18)	27	19
Net cash provided by (used in) financing activities	(1,285)	(987)	635
Net decrease in cash and cash equivalents	(240)	(367)	(798)
Cash and cash equivalents at beginning of period	1,127	1,494	2,292
Cash and cash equivalents at end of period	$ 887	$ 1,127	$ 1,494

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 Income (Loss)	Non-controlling Interests
Beginning balance at Dec. 31, 2013	$ 11,332	$ 7	$ (4,155)	$ 9,765	$ 5,507	$ (204)	$ 412
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,555				2,524		31
Dividends declared	(525)				(525)
Distributions to noncontrolling interests	(27)						(27)
Other comprehensive income (loss)	(109)					(109)
Shares repurchased	(2,131)		(2,131)
Shares returned - stock based compensation			(13)
Shares issued - stock based compensation				26
Shares issued (returned) – stock-based compensation	13
Stock-based compensation	52			50			2
Impact from equity transactions of MPLX LP	221						221
Other	9				9
Ending balance at Dec. 31, 2014	11,390	7	(6,299)	9,841	7,515	(313)	639
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,868				2,852		16
Dividends declared	(615)				(615)
Distributions to noncontrolling interests	(40)						(40)
Other comprehensive income (loss)	(5)					(5)
Shares repurchased	(965)		(965)
Shares returned - stock based compensation			(11)
Shares issued - stock based compensation				33
Shares issued (returned) – stock-based compensation	22
Stock-based compensation	85			69			16
Impact from equity transactions of MPLX LP	6,923			1,128			5,795
Noncontrolling interest - MarkWest Merger	13						13
Other	(1)						(1)
Ending balance at Dec. 31, 2015	19,675	7	(7,275)	11,071	9,752	(318)	6,438
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	1,172				1,174		(2)
Dividends declared	(720)				(720)
Distributions to noncontrolling interests	(517)						(517)
Other comprehensive income (loss)	84					84
Shares repurchased	(197)		(197)
Shares returned - stock based compensation			(10)
Shares issued - stock based compensation				11
Shares issued (returned) – stock-based compensation	1
Stock-based compensation	41			35			6
Impact from equity transactions of MPLX LP	658			(57)			715
Other	6						6
Ending balance at Dec. 31, 2016	$ 20,203	$ 7	$ (7,482)	$ 11,060	$ 10,206	$ (234)	$ 6,646

Consolidated Statements of Eq10

Consolidated Statements of Equity - Shares - shares shares in Millions	Total	Common Stock	Treasury Stock
Number of shares issued (beginning balance) at Dec. 31, 2013		724
Number of shares issued - stock-based compensation		2
Number of shares issued (ending balance) at Dec. 31, 2014		726
Number of shares held in treasury (beginning balance) at Dec. 31, 2013			(130)
Number of shares repurchased	(49)		(49)
Number of shares held in treasury (ending balance) at Dec. 31, 2014			(179)
Number of shares issued - stock-based compensation		3
Number of shares issued (ending balance) at Dec. 31, 2015	729	729
Number of shares repurchased	(19)		(19)
Number of shares held in treasury (ending balance) at Dec. 31, 2015	(198)		(198)
Number of shares issued - stock-based compensation		2
Number of shares issued (ending balance) at Dec. 31, 2016	731	731
Number of shares repurchased	(4)		(4)
Number of shares returned - stock-based compensation			(1)
Number of shares held in treasury (ending balance) at Dec. 31, 2016	(203)		(203)

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interest $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Temporary Equity [Abstract]
Redeemable noncontrolling interest, beginning balance	$ 0
Net income (loss) attributable to redeemable noncontrolling interest	41
Distributions to noncontrolling interests	(25)
Issuance of MPLX LP redeemable preferred units	984
Redeemable noncontrolling interest, ending balance	$ 1,000

Description Of The Business And

Description Of The Business And Basis Of Presentation	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Description of the Business and Basis of Presentation	Description of the Business and Basis of Presentation Description of the Business – Our business consists of refining and marketing, retail and midstream services conducted primarily in the Midwest, Gulf Coast, East Coast, Northeast and Southeast regions of the United States, through subsidiaries, including Marathon Petroleum Company LP, Speedway LLC and its subsidiaries (“Speedway”) and MPLX LP and its subsidiaries (“MPLX”). See Note 10 for additional information about our operations. Spinoff – On May 25, 2011, the Marathon Oil board of directors approved the spinoff of its Refining, Marketing & Transportation Business (“RM&T Business”) into an independent, publicly traded company, MPC, through the distribution of MPC common stock to the stockholders of Marathon Oil common stock (the “Spinoff”). MPC became an independent, publicly traded company on July 1, 2011. Basis of Presentation – Our results of operations and cash flows consist of consolidated MPC activities. All significant intercompany transactions and accounts have been eliminated. Certain prior period financial statement amounts have been reclassified to conform to current period presentation. In the first quarter of 2016, we revised our segment reporting in connection with the contribution of our inland marine business to MPLX. See Note 4 for additional information. The operating results for our inland marine business and our investment in an ocean vessel joint venture, Crowley Ocean Partners LLC (“Crowley Ocean Partners”) are now reported in our Midstream segment. Previously they were reported as part of our Refining & Marketing segment. Comparable prior period information has been recast to reflect our revised segment presentation. See Note 10 for additional information.

Summary Of Principal Accounting

Summary Of Principal Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary Of Principal Accounting Policies	Summary of Principal Accounting Policies Principles applied in consolidation – These consolidated financial statements include the accounts of our majority-owned, controlled subsidiaries and MPLX. Changes in ownership interest in consolidated subsidiaries that do not result in a change in control are recorded as an equity transaction. As of December 31, 2016 , we owned a 25.5 percent interest in MPLX, including a two percent general partner interest. This ownership percentage reflects the conversion of the MPLX Class B Units in July 2017 at 1.09 to 1.00. Due to our 100 percent ownership of the general partner interest, we have determined that we control MPLX and therefore we consolidate MPLX and record a noncontrolling interest for the 74.5 percent interest owned by the public. Investments in entities over which we have significant influence, but not control, are accounted for using the equity method of accounting. This includes entities in which we hold majority ownership but the minority shareholders have substantive participating rights. Income from equity method investments represents our proportionate share of net income generated by the equity method investees. Differences in the basis of the investments and the separate net asset values of the investees, if any, are amortized into net income over the remaining useful lives of the underlying assets and liabilities, except for the excess related to goodwill. Equity method investments are evaluated for impairment whenever changes in the facts and circumstances indicate an other than temporary loss in value has occurred. When the loss is deemed to be other than temporary, the carrying value of the equity method investment is written down to fair value, and the amount of the write-down is included in net income. Use of estimates – The preparation of financial statements in accordance with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods. Revenue recognition – Revenues are recognized when products are shipped or services are provided to customers, title is transferred, the sales price is fixed or determinable and collectability is reasonably assured. Costs associated with revenues are recorded in cost of revenues. Shipping and other transportation costs billed to our customers are presented on a gross basis in revenues and cost of revenues. Rebates from vendors are recognized as a reduction of cost of revenues when the initiating transaction occurs. Incentives that are derived from contractual provisions are accrued based on past experience and recognized in cost of revenues. Rebates to customers are reflected as a reduction of revenue and are accrued for in “Accounts payable” on the consolidated balance sheets. Crude oil and refined product exchanges and matching buy/sell transactions – We enter into exchange contracts and matching buy/sell arrangements whereby we agree to deliver a particular quantity and quality of crude oil or refined products at a specified location and date to a particular counterparty and to receive from the same counterparty the same commodity at a specified location on the same or another specified date. The exchange receipts and deliveries are nonmonetary transactions, with the exception of associated grade or location differentials that are settled in cash. The matching buy/sell purchase and sale transactions are settled in cash. Both exchange and matching buy/sell transactions are accounted for as exchanges of inventory and no revenues are recorded. The exchange transactions are recognized at the carrying amount of the inventory transferred. Consumer excise taxes – We are required by various governmental authorities, including countries, states and municipalities, to collect and remit taxes on certain consumer products. Such taxes are presented on a gross basis in revenues and costs and expenses in the consolidated statements of income. Cash and cash equivalents – Cash and cash equivalents include cash on hand and on deposit and investments in highly liquid debt instruments with maturities of three months or less. Restricted cash – Restricted cash consists of cash and investments that must be maintained as collateral for letters of credit issued to certain third party producer customers. The balances will be outstanding until certain capital projects are completed and the third party releases the restriction. Restricted cash also consists of cash advances to be used for the operation and maintenance of an operated pipeline system. At December 31, 2016 and 2015 , the amount of restricted cash included in “Other current assets” on the consolidated balance sheets were $5 million and $9 million , respectively, which is currently reflected in our Midstream segment. Accounts receivable and allowance for doubtful accounts – Our receivables primarily consist of customer accounts receivable. Customer receivables are recorded at the invoiced amounts and generally do not bear interest. Allowances for doubtful accounts are generally recorded when it becomes probable the receivable will not be collected and are booked to bad debt expense. The allowance for doubtful accounts is the best estimate of the amount of probable credit losses in customer accounts receivable. We review the allowance quarterly and past-due balances over 180 days are reviewed individually for collectability. Approximately 23 percent and 26 percent of our accounts receivable balances at December 31, 2016 and 2015 , respectively, are related to sales of crude oil or refinery feedstocks to customers with whom we have master netting agreements. We have master netting agreements with more than 100 companies engaged in the crude oil or refinery feedstock trading and supply business or the petroleum refining industry. A master netting agreement generally provides for a once per month net cash settlement of the accounts receivable from and the accounts payable to a particular counterparty. Inventories – Inventories are carried at the lower of cost or market value. Cost of inventories is determined primarily under the LIFO method. Costs for crude oil, refinery feedstocks and refined product inventories are aggregated on a consolidated basis for purposes of assessing if the LIFO cost basis of these inventories may have to be written down to market value. Derivative instruments – We use derivatives to economically hedge a portion of our exposure to commodity price risk and, historically, to interest rate risk. We also have limited authority to use selective derivative instruments that assume market risk. All derivative instruments (including derivative instruments embedded in other contracts) are recorded at fair value. Certain commodity derivatives are reflected on the consolidated balance sheets on a net basis by counterparty as they are governed by master netting agreements. Cash flows related to derivatives used to hedge commodity price risk and interest rate risk are classified in operating activities with the underlying transactions. Fair value accounting hedges – We used interest rate swaps to hedge our exposure to interest rate risk associated with fixed interest rate debt in our portfolio. These interest rate swap agreements were terminated in 2012. Changes in the fair values of both the hedged item and the related derivative were recognized immediately in net income with an offsetting effect included in the basis of the hedged item. The net effect was to report in net income the extent to which the accounting hedge was not effective in achieving offsetting changes in fair value. There was a gain on the termination of the agreements, which had been deferred and accounted for as an adjustment to our long-term debt balance. The gain was being amortized over the remaining life of the associated debt as a reduction of our interest expense, until the December 2015 extinguishment of our obligation for the associated debt. At such time, the remaining unamortized gain was credited to net interest and other financial income (costs). Derivatives not designated as accounting hedges – 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, (6) the purchase of natural gas and (7) the purchase of electricity. Changes in the fair value of derivatives not designated as accounting hedges are recognized immediately in net income. Concentrations of credit risk – All of our financial instruments, including derivatives, involve elements of credit and market risk. The most significant portion of our credit risk relates to nonperformance by counterparties. The counterparties to our financial instruments consist primarily of major financial institutions and companies within the energy industry. To manage counterparty risk associated with financial instruments, we select and monitor counterparties based on an assessment of their financial strength and on credit ratings, if available. Additionally, we limit the level of exposure with any single counterparty. Property, plant and equipment – Property, plant and equipment are recorded at cost and depreciated on a straight-line basis over the estimated useful lives of the assets, which range from two to 42 years. Such assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the expected undiscounted future cash flows from the use of the asset and its eventual disposition is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset. When items of property, plant and equipment are sold or otherwise disposed of, any gains or losses are reported in net income. Gains on the disposal of property, plant and equipment are recognized when earned, which is generally at the time of closing. If a loss on disposal is expected, such losses are recognized when the assets are classified as held for sale. Interest expense is capitalized for qualifying assets under construction. Capitalized interest costs are included in property, plant and equipment and are depreciated over the useful life of the related asset. Goodwill and intangible assets – Goodwill represents the excess of the purchase price over the estimated fair value of the net assets acquired in the acquisition of a business. Goodwill is not amortized, but rather is tested for impairment annually and when events or changes in circumstances indicate that the fair value of a reporting unit with goodwill has been reduced below carrying value. The impairment test requires allocating goodwill and other assets and liabilities to reporting units. The fair value of each reporting unit is determined and compared to the carrying value of the reporting unit. If the fair value of the reporting unit is less than the carrying value, including goodwill, the implied fair value of goodwill is calculated. The excess, if any, of the book value over the implied fair value of goodwill is charged to net income as an impairment expense. Amortization of intangibles with definite lives is calculated using the straight-line method which is reflective of the benefit pattern in which the estimated economic benefit is expected to be received over the estimated useful life of the intangible asset. Intangibles subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the intangible may not be recoverable. If the sum of the expected undiscounted future cash flows related to the asset is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset. Intangibles not subject to amortization are tested for impairment annually and when circumstances indicate that the fair value is less than the carrying amount of the intangible. If the fair value is less than the carrying value, an impairment is recorded for the difference. Major maintenance activities – Costs for planned turnaround, major maintenance and engineered project activities are expensed in the period incurred. These types of costs include contractor repair services, materials and supplies, equipment rentals and our labor costs. Environmental costs – Environmental expenditures are capitalized for additional equipment that mitigates or prevents future contamination or improves environmental safety or efficiency of the existing assets. We recognize remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs can be reasonably estimated. The timing of remediation accruals coincides with completion of a feasibility study or the commitment to a formal plan of action. Remediation liabilities are accrued based on estimates of known environmental exposure and are discounted when the estimated amounts are reasonably fixed and determinable. If recoveries of remediation costs from third parties are probable, a receivable is recorded and is discounted when the estimated amount is reasonably fixed and determinable. Asset retirement obligations – The fair value of asset retirement obligations is recognized in the period in which the obligations are incurred if a reasonable estimate of fair value can be made. The majority of our recognized asset retirement liability relates to conditional asset retirement obligations for removal and disposal of fire-retardant material from certain refining facilities. The remaining recognized asset retirement liability relates to other refining assets, the removal of underground storage tanks at our leased convenience stores, certain pipelines and processing facilities and other related pipeline assets. The fair values recorded for such obligations are based on the most probable current cost projections. The recorded asset retirement obligations are not material to the consolidated financial statements. Asset retirement obligations have not been recognized for some assets because the fair value cannot be reasonably estimated since the settlement dates of the obligations are indeterminate. Such obligations will be recognized in the period when sufficient information becomes available to estimate a range of potential settlement dates. The asset retirement obligations principally include the hazardous material disposal and removal or dismantlement requirements associated with the closure of certain refining, terminal, retail, pipeline and processing assets. Our practice is to keep our assets in good operating condition through routine repair and maintenance of component parts in the ordinary course of business and by continuing to make improvements based on technological advances. As a result, we believe that generally these assets have no expected settlement date for purposes of estimating asset retirement obligations since the dates or ranges of dates upon which we would retire these assets cannot be reasonably estimated at this time. Income taxes – Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their tax bases. Deferred tax assets are recorded when it is more likely than not that they will be realized. The realization of deferred tax assets is assessed periodically based on several factors, primarily our expectation to generate sufficient future taxable income. Stock-based compensation arrangements – The fair value of stock options granted to our employees is estimated on the date of grant using the Black-Scholes option pricing model. The model employs various assumptions, based on management’s estimates at the time of grant, which impact the calculation of fair value and ultimately, the amount of expense that is recognized over the vesting period of the stock option award. Of the required assumptions, the expected life of the stock option award and the expected volatility of our stock price have the most significant impact on the fair value calculation. The average expected life is based on our historical employee exercise behavior. The assumption for expected volatility of our stock price reflects a weighting of 50 percent of our common stock implied volatility and 50 percent of our common stock historical volatility. The fair value of restricted stock awards granted to our employees is determined based on the fair market value of our common stock on the date of grant. The fair value of performance unit awards granted to our employees is estimated on the date of grant using a Monte Carlo valuation model. Our stock-based compensation expense is recognized based on management’s estimate of the awards that are expected to vest, using the straight-line attribution method for all service-based awards with a graded vesting feature. If actual forfeiture results are different than expected, adjustments to recognized compensation expense may be required in future periods. Unearned stock-based compensation is charged to equity when restricted stock awards are granted. Compensation expense is recognized over the vesting period and is adjusted if conditions of the restricted stock award are not met. Business combinations - We recognize and measure the assets acquired and liabilities assumed in a business combination based on their estimated fair values at the acquisition date, with any remaining difference versus the purchase consideration recorded as goodwill or gain from a bargain purchase. For all material acquisitions, management engages an independent valuation specialist to assist with the determination of fair value of the assets acquired, liabilities assumed, noncontrolling interest, if any, and goodwill, based on recognized business valuation methodologies. If the initial accounting for the business combination is incomplete by the end of the reporting period in which the acquisition occurs, an estimate will be recorded. Subsequent to the acquisition, and not later than one year from the acquisition date, we will record any material adjustments to the initial estimate based on new information obtained about facts and circumstances that existed as of the acquisition date. An income, market or cost valuation method may be utilized to estimate the fair value of the assets acquired, liabilities assumed, and noncontrolling interest, if any, in a business combination. The income valuation method represents the present value of future cash flows over the life of the asset using: (i) discrete financial forecasts, which rely on management’s estimates of revenue and operating expenses; (ii) long-term growth rates; and (iii) appropriate discount rates. The market valuation method uses prices paid for a reasonably similar asset by other purchasers in the market, with adjustments relating to any differences between the assets. The cost valuation method is based on the replacement cost of a comparable asset at prices at the time of the acquisition reduced for depreciation of the asset. Acquisition-related costs are expensed as incurred in connection with each business combination. Renewable fuel identification numbers – We purchase RINs to satisfy a portion of our RFS2 compliance. We record a short-term intangible asset, included in “Other current assets” on the balance sheet, for RINs owned in excess of our anticipated current period compliance requirements. The asset value is based on the product of the excess RINs as of the balance sheet date, if any, and the average cost of our RINs. We record a current liability, included in “Other current liabilities” on the balance sheet, when we are deficient RINs based on the product of the deficient RINs as of the balance sheet date, if any, and the market price of the RINs at the balance sheet date. The cost of RINs used for compliance is reflected in “Cost of revenues” on the income statement. Any gains or losses on the sale or expiration of RINs are classified as “Other income” on the income statement. Proceeds from RIN sales are included in investing activities - “All other, net” on the cash flow statement.

Accounting Standards

Accounting Standards	12 Months Ended
	Dec. 31, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Adopted Accounting Pronouncements	Accounting Standards Recently Adopted In September 2015, the FASB issued an accounting standard update that eliminates the requirement to restate prior period financial statements for measurement period adjustments related to business combinations. This accounting standard update requires that the cumulative impact of a measurement period adjustment be recognized in the reporting period in which the adjustment is identified. The change was effective for interim and annual periods beginning after December 15, 2015. We recognized measurement period adjustments during the first and second quarters of 2016 on a cumulative prospective basis as additional analysis was completed on the preliminary purchase price allocation for the acquisition of MarkWest Energy Partners, L.P. (“MarkWest”). See Note 5 for further discussion and detail related to these measurement period adjustments. In May 2015, the FASB issued an accounting standard update that eliminates the requirement to categorize investments that are measured at net asset value using the practical expedient in the fair value hierarchy. The change was effective for fiscal years beginning after December 15, 2015 and interim periods within the fiscal year. Retrospective application is required. Adoption of this accounting standard update in the first quarter of 2016 did not have a material impact on our disclosures. In April 2015, the FASB issued an accounting standard update clarifying whether a customer should account for a cloud computing arrangement as an acquisition of a software license or as a service arrangement by providing characteristics that a cloud computing arrangement must have in order to be accounted for as a software license acquisition. The change was effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Retrospective or prospective application is allowed. We adopted this accounting standard update prospectively in the first quarter of 2016 and it did not have a material impact on our consolidated financial statements. In February 2015, the FASB issued an accounting standard update making targeted changes to the current consolidation guidance. The accounting standard update changes the considerations related to substantive rights, related parties, and decision making fees when applying the VIE consolidation model and eliminates certain guidance for limited partnerships and similar entities under the voting interest consolidation model. The change was effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Under the accounting standard update, we continue to consolidate our master limited partnership, MPLX, but it is now considered to be a VIE. The adoption of this accounting standard update in the first quarter of 2016 did impact our disclosures for this consolidated VIE, but did not have a material impact on our consolidated financial statements. In August 2014, the FASB issued an accounting standard update requiring management to assess an entity’s ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. Management is required to assess if there is substantial doubt about an entity’s ability to continue as a going concern within one year after the issuance of the financial statements. Disclosures are required if conditions give rise to substantial doubt and the type of disclosure is determined based on whether management’s plans will be able to alleviate the substantial doubt. The change was effective for the first fiscal year ending after December 15, 2016, and for fiscal years and interim periods thereafter. The adoption of this accounting standard update in the fourth quarter of 2016 did not have a material impact on our disclosures. In June 2014, the FASB issued an accounting standard update for the elimination of the concept of development stage entity (“DSE”) from U.S. GAAP and removes the related incremental reporting. The accounting standard update eliminated the additional financial statement requirements specific to a DSE and was adopted in the first quarter of 2015. In addition, the portion of the accounting standard update that amended the consolidation model to eliminate the special provisions in the VIE rules for assessing the sufficiency of the equity of a DSE was adopted in the first quarter of 2016. Adoption of this accounting standard update in the first quarters of 2015 and 2016 did not have an impact on our consolidated financial statements.
Not Yet Adopted Accounting Pronouncements	Not Yet Adopted In January 2017, the FASB issued an accounting standard update 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; 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. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. In January 2017, the FASB issued an accounting standard update to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The standard is intended to narrow the definition of a business by specifying the minimum inputs and processes and by narrowing the definition of outputs. The change is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The guidance will be applied prospectively and early adoption is permitted for certain transactions. We are in the process of determining the impact of the accounting standard update on the consolidated financial statements. In November 2016, the FASB issued an accounting standard update requiring that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The change is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. Retrospective application is required. The application of this accounting standard update will not have a material impact on our statements of cash flows. In October 2016, the FASB issued an accounting standard update to amend the consolidation guidance issued in February 2015 to require that a decision maker consider, in the determination of the primary beneficiary, its indirect interest in a VIE held by a related party that is under common control on a proportionate basis only. The change is effective for our financial statements for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years, with early adoption permitted. We are required to apply the standard retrospective to January 1, 2016, the date on which we adopted the consolidation guidance issued in February 2015. We have analyzed this accounting standard update and do not expect there to be an impact on our consolidated financial statements. In October 2016, the FASB issued an accounting standard update that requires recognition of the income tax consequences of intra-entity transfers of assets other than inventory when the transfer occurs. The change is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. The amendments in this accounting standard update should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. We do not expect application of this accounting standard update to have a material impact on our consolidated financial statements. In August 2016, the FASB issued an accounting standard update related to the classification of certain cash flows. The accounting standard update provides specific guidance on eight cash flow classification issues, including debt prepayment or debt extinguishment costs, contingent consideration payments made after a business combination and distributions received from equity method investees, to reduce diversity in practice. The change is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. We do not expect application of this accounting standard update to have a material impact on our statements of cash flows. In June 2016, the FASB issued an accounting standard update 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 accounting standard update to have a material impact on our consolidated financial statements. In March 2016, the FASB issued an accounting standard update to simplify some provisions in stock compensation accounting. The areas for simplification involve the accounting for share-based payment transactions, including income tax consequences, classifications of awards as either equity or liabilities and classification within the statement of cash flows. The changes are effective for fiscal years beginning after December 15, 2016, and interim periods within those years, and early adoption is permitted. Adoption of this accounting standard update in the first quarter of 2017 will not have a material impact on our consolidated financial statements. In March 2016, the FASB issued an accounting standard update eliminating the requirement that an investor retrospectively apply equity method accounting when an investment that it had accounted for by another method initially qualifies for the equity method. This change will be effective for fiscal years beginning after December 15, 2016, and interim periods within those years. The guidance will be applied prospectively and early adoption is permitted. We do not expect application of this accounting standard update to have a material impact on our consolidated financial statements. In February 2016, the FASB issued an accounting standard update requiring lessees to record virtually all leases on their balance sheets. The accounting standard update also requires expanded disclosures to help financial statement users better understand the amount, timing and uncertainty of cash flows arising from leases. For lessors, this amended guidance modifies the classification criteria and the accounting for sales-type and direct financing leases. The change will be effective on a modified retrospective basis for fiscal years beginning after December 15, 2018, and interim periods within those years, with early adoption permitted. We are currently evaluating the impact of this standard on our financial statements and disclosures, internal controls and accounting policies. This evaluation process includes reviewing all forms of leases, performing a completeness assessment over lease population and analyzing the practical expedients in order to determine the best path of implementation. We expect to recognize an asset and obligation related to leases previously accounted for as operating leases. In January 2016, the FASB issued an accounting standard update requiring unconsolidated equity investments, not accounted for under the equity method, to be measured at fair value with changes in fair value recognized in net income. The accounting standard update also requires the use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes and the separate presentation of financial assets and liabilities by measurement category and form on the balance sheet and accompanying notes. The accounting standard update eliminates the requirement to disclose the methods and assumptions used in estimating the fair value of financial instruments measured at amortized cost. Lastly, the accounting standard update requires separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when electing to measure the liability at fair value in accordance with the fair value option for financial instruments. The changes are effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2017. Early adoption is permitted only for the guidance regarding presentation of a liability’s credit risk. We do not expect application of this accounting standard update to have a material impact on our consolidated financial statements. In May 2014, the FASB issued an accounting standard update for revenue recognition for contracts with customers. The guidance in the accounting standard update states that revenue is recognized when a customer obtains control of a good or service. Recognition of the revenue will involve a multiple step approach including identifying the contract, identifying the separate performance obligations, determining the transaction price, allocating the price to the performance obligations and then recognizing the revenue as the obligations are satisfied. Additional disclosures will be required to provide adequate information to understand the nature, amount, timing and uncertainty of reported revenues and revenues expected to be recognized. The change will be effective on a retrospective or modified retrospective basis for fiscal years beginning after December 15, 2017, and interim periods within those years, with early adoption permitted, no earlier than January 1, 2017. We are currently evaluating the impact of this standard on our financial statements and disclosures, internal controls and accounting policies. This evaluation process is primarily focused on reviewing service contracts and transaction types across our Midstream segment. We are also evaluating the election allowing for net reporting included in the accounting standard update for consumer excise taxes. In addition, we are currently evaluating the methods of adoption.

MPLX LP

MPLX LP	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
MPLX LP	MPLX LP MPLX is a diversified, growth-oriented publicly traded master limited partnership initially formed by us to own, operate, develop and acquire midstream assets related to the transportation and storage of hydrocarbon-based products, including crude oil, refined products, natural gas and NGLs. On December 4, 2015, MPLX and MarkWest Energy Partners, L.P. (“MarkWest”) completed a merger, whereby MarkWest became a wholly-owned subsidiary of MPLX (the “MarkWest Merger”). MarkWest’s operations include: natural gas gathering, processing and transportation; and NGL gathering, transportation, fractionation, storage and marketing. MPLX’s other assets include a 100 percent interest in MPLX Pipe Line Holdings LLC (“Pipe Line Holdings”), which owns a network of common carrier crude oil and product pipeline systems and associated storage assets in the Midwest and Gulf Coast regions of the United States and a 100 percent interest in a butane cavern in Neal, West Virginia. MPLX also owns an inland marine business, which is comprised of 18 tow boats and approximately 200 barges which transports crude oil and refined products principally for MPC in the Midwest and Gulf Coast regions of the United States. See Note 5 for information on MPLX’s investment in the Bakken Pipeline system. As of December 31, 2016 , we owned a 25.5 percent interest in MPLX, including a two percent general partner interest. This ownership percentage reflects the conversion of the MPLX Class B Units in July 2017 at 1.09 to 1.00. MPLX is a VIE because the limited partners of MPLX do not have substantive kick-out or substantive participating rights over the general partner. We are the primary beneficiary of MPLX because in addition to our significant economic interest, we also have the power, through our 100 percent ownership of the general partner, to control the decisions that most significantly impact MPLX. We therefore consolidate MPLX and record a noncontrolling interest for the 74.5 percent interest owned by the public. The components of our noncontrolling interest consist of equity-based noncontrolling interest and redeemable noncontrolling interest. The redeemable noncontrolling interest relates to MPLX’s preferred units, discussed below. The creditors of MPLX do not have recourse to MPC’s general credit through guarantees or other financial arrangements. The assets of MPLX are the property of MPLX and cannot be used to satisfy the obligations of MPC. Reorganization Transactions On September 1, 2016, MPC, MPLX and various affiliates initiated a series of reorganization transactions in order to simplify MPLX’s ownership structure and its financial and tax reporting. In connection with these transactions, MPC contributed $225 million to MPLX, and all of the issued and outstanding MPLX Class A Units, all of which were held by MarkWest Hydrocarbon L.L.C. (“MarkWest Hydrocarbon”), a subsidiary of MPLX, were exchanged for newly issued common units representing limited partner interests in MPLX. The simple average of the closing prices of MPLX common units for the last 10 trading days prior to September 1, 2016 was used for purposes of these transactions. As a result of these transactions, MPC increased its ownership interest in MPLX by 7 million MPLX common units, or approximately 1 percent . Private Placement of Preferred Units On May 13, 2016, MPLX completed the private placement of approximately 30.8 million 6.5 percent Series A Convertible Preferred Units (the “MPLX Preferred Units”) at a cash price of $32.50 per unit. The aggregate net proceeds of approximately $984 million from the sale of the MPLX Preferred Units was used for capital expenditures, repayment of debt and general partnership purposes. The MPLX Preferred Units rank senior to all MPLX common units with respect to distributions and rights upon liquidation. The holders of the MPLX Preferred Units are entitled to receive quarterly distributions equal to $0.528125 per unit commencing for the quarter ended June 30, 2016, with a prorated amount from the date of issuance. Following the second anniversary of the issuance of the MPLX Preferred Units, the holders of the MPLX Preferred Units will receive as a distribution the greater of $0.528125 per unit or the amount of per unit distributions paid to common unitholders. The MPLX Preferred Units are convertible into MPLX common units on a one for one basis after three years, at the purchasers’ option, and after four years at MPLX’s option, subject to certain conditions. The MPLX Preferred Units are considered redeemable securities due to the existence of redemption provisions upon a deemed liquidation event which is considered outside MPLX’s control. Therefore they are presented as temporary equity in the mezzanine section of the consolidated balance sheets. We have recorded the MPLX Preferred Units at their issuance date fair value, net of issuance costs. Since the MPLX Preferred Units are not currently redeemable and not probable of becoming redeemable in the future, adjustment to the initial carrying amount is not necessary and would only be required if it becomes probable that the security would become redeemable. Dropdowns to MPLX On March 1, 2014, we sold MPLX a 13 percent interest in Pipe Line Holdings for $310 million . MPLX financed this transaction with $40 million of cash on-hand and $270 million of borrowings on its bank revolving credit facility. On December 1, 2014, we sold and contributed interests in Pipe Line Holdings totaling 30.5 percent to MPLX for $600 million in cash and 2.9 million MPLX common units valued at $200 million . MPLX financed the sales portion of this transaction with $600 million of borrowings on its bank revolving credit facility. On December 4, 2015, we sold our remaining 0.5 percent interest in Pipe Line Holdings to MPLX for $12 million . As a result, MPLX now owns 100 percent of Pipe Line Holdings. The sales and contribution of our interests in Pipe Line Holdings to MPLX resulted in a change of our ownership in Pipe Line Holdings, but not a change in control. We accounted for these sales as transactions between entities under common control and did not record a gain or loss. On March 31, 2016, we contributed our inland marine business to MPLX in exchange for 23 million MPLX common units and 460 thousand MPLX general partner units. The number of units we received from MPLX was determined by dividing $600 million by the volume weighted average NYSE price of MPLX common units for the 10 trading days preceding March 14, 2016, pursuant to the Membership Interests Contribution Agreement. We also agreed to waive first-quarter 2016 common unit distributions, IDRs and general partner distributions with respect to the common units issued in this transaction. The contribution of our inland marine business was accounted for as a transaction between entities under common control and therefore, we did not record a gain or loss. On December 5, 2016, our board of directors authorized us to offer up to 100 percent of MPLX Terminals LLC (“MPLX Terminals”), Hardin Street Transportation LLC (“Hardin Street Transportation”) and Woodhaven Cavern LLC (“Woodhaven Cavern”) to MPLX. MPLX Terminals owns and operates terminal and marine facilities. Hardin Street Transportation owns and operates various private crude oil and refined product pipeline systems and associated storage tanks as well as several condensate truck loading and unloading facilities. Woodhaven Cavern owns and operates butane and propane storage caverns. The transaction is expected to close in the first quarter of 2017, pending requisite approvals. Public Offerings On December 8, 2014, MPLX completed a public offering of 3.5 million common units at a price to the public of $66.68 per MPLX common unit, with net proceeds of $221 million . MPLX used the net proceeds from this offering to repay borrowings under its bank revolving credit facility and for general partnership purposes. On February 12, 2015, MPLX completed a public offering of $500 million aggregate principal amount of four percent unsecured senior notes due February 15, 2025 . See Note 19 for more information. ATM Program On August 4, 2016, MPLX entered into a Second Amended and Restated Distribution Agreement (the “Distribution Agreement”) providing for the continuous issuance of common units, in amounts, at prices and on terms to be determined by market conditions and other factors at the time of any offerings (such continuous offering program, or at-the-market program, referred to as the “ATM Program”). MPLX expects to use the net proceeds from sales under the ATM Program for general partnership purposes including repayment of debt and funding for acquisitions, working capital requirements and capital expenditures. During 2016 , MPLX issued an aggregate of 26 million MPLX common units under the ATM Program, generating net proceeds of approximately $776 million . As of December 31, 2016 , $717 million of MPLX common units remains available for issuance through the ATM Program under the Distribution Agreement. Noncontrolling Interest Changes in MPC’s equity resulting from changes in its ownership interest in MPLX were as follows: (In millions) 2016 2015 Transfers (to) from noncontrolling interest Increase (decrease) in MPC's paid in capital for the issuance of MPLX LP common units to the public $ (60 ) $ 1,532 Increase in MPC's paid in capital for the issuance of MPLX LP common units and general partner units to MPC 121 — Net transfers (to) from noncontrolling interests 61 1,532 Tax impact (118 ) (404 ) Change in MPC's additional paid-in capital, net of tax $ (57 ) $ 1,128 Agreements We have various long-term, fee-based transportation and storage services agreements with MPLX. Under these agreements, MPLX provides transportation and storage services to us, and we commit to provide MPLX with minimum quarterly throughput volumes on crude oil and refined products systems and minimum storage volumes of crude oil, refined products and butane. We also have agreements with MPLX which 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.

Acquisitions and Investments

Acquisitions and Investments	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisitions and Investments	Acquisitions and Investments Merger with MarkWest Energy Partners, L.P. On December 4, 2015, MPLX completed the MarkWest Merger. Each common unit of MarkWest issued and outstanding immediately prior to the effective time of the MarkWest Merger was converted into a right to receive 1.09 common units of MPLX representing limited partner interests in MPLX, plus a one-time cash payment of $6.20 per unit. We will contribute approximately $1.28 billion of cash to MPLX to pay the aggregate cash consideration to MarkWest unitholders, without receiving any new equity from MPLX in exchange. At closing, we made a payment of $1.23 billion to MarkWest common unitholders and the remaining $50 million will be paid in equal amounts, the first $25 million was paid in July 2016 and the second $25 million will be paid in July 2017, in connection with the conversion of the MPLX Class B Units to MPLX common units. Our financial results and operating statistics reflect the results of MarkWest from the date of the MarkWest Merger. The components of the fair value of consideration transferred are as follows: (In millions) Fair value of MPLX units issued $ 7,326 Cash payment to MarkWest unitholders 1,230 Payable to MarkWest Class B unitholders 50 Total fair value of consideration transferred $ 8,606 The following table summarizes the final purchase price allocation. Subsequent to December 31, 2015, additional analysis was completed and adjustments were made to the preliminary purchase price allocation as noted in the table below. The estimated fair value of assets acquired and liabilities and noncontrolling interests assumed at the acquisition date, are as follows: (In millions) As originally reported Adjustments As adjusted Cash and cash equivalents $ 12 $ — $ 12 Receivables 164 — 164 Inventories 33 (1 ) 32 Other current assets 44 — 44 Equity method investments 2,457 143 2,600 Property, plant and equipment, net 8,474 43 8,517 Other noncurrent assets (a) 473 65 538 Total assets acquired 11,657 250 11,907 Accounts payable 322 6 328 Payroll and benefits payable 13 — 13 Accrued taxes 21 — 21 Other current liabilities 44 — 44 Long-term debt 4,567 — 4,567 Deferred income taxes 374 3 377 Deferred credit and other liabilities 151 — 151 Noncontrolling interests 13 — 13 Total liabilities and noncontrolling interest assumed 5,505 9 5,514 Net assets acquired excluding goodwill 6,152 241 6,393 Goodwill 2,454 (241 ) 2,213 Net assets acquired $ 8,606 $ — $ 8,606 (a) The adjustment relates to acquired intangible assets. Included in noncurrent assets at December 31, 2015 was a $468 million intangible asset related to customer contracts and relationships. Amortization of intangibles with definite lives was calculated using the straight-line method which was reflective of the benefit pattern in which the estimated economic benefit was expected to be received over the estimated useful life of the intangible asset. The estimated useful life of the customer contracts and relationships is 11 to 25 years. Adjustments to the preliminary purchase price allocations as of December 31, 2015 stem mainly from additional information obtained by management in the first quarter about facts and circumstances that existed at the acquisition date including updates to forecasted employee benefit costs and capital expenditures, and completion of certain valuations to determine the underlying fair value of certain acquired assets. The adjustment to intangibles mainly relates to a misstatement in the preliminary purchase price allocation as of December 31, 2015. The correction of the error resulted in a $68 million reduction to the carrying value of goodwill and offsetting increases of $64 million in intangibles and $2 million in both equity method investments and property, plant and equipment. Management concluded that the correction of the error is immaterial to the consolidated financial statements for all periods presented. The increases to fair value of equity method investments, property plant and equipment, and other noncurrent assets noted above would not have resulted in a material effect to depreciation and amortization or income from equity method investments in the consolidated statements of income for the year ended December 31, 2015, had the fair value adjustments been recorded as of December 4, 2015. The net fair value of the assets acquired and liabilities assumed in connection with the MarkWest Merger was less than the fair value of the total consideration resulting in the recognition of $2.21 billion of goodwill in three reporting units within our Midstream segment, substantially all of which is not deductible for tax purposes. Goodwill represents the complimentary aspects of the highly diverse asset base of MarkWest and MPLX that will provide significant additional opportunities across the hydrocarbon value chain. As further discussed in Note 16 , we recorded a goodwill impairment charge based on the implied fair value of goodwill as of the interim impairment analysis in the first quarter of 2016. During the second quarter of 2016, we finalized the analysis of the purchase price allocation. The completion of the purchase price allocation resulted in a refinement of the impairment expense recorded, as more fully discussed in Note 16 . We recognized $36 million of transaction costs related to the MarkWest Merger. These costs were expensed and $30 million is included in selling, general and administrative expenses and $6 million is in net interest and other financial income (costs). The amounts of revenue and income from operations associated with the MarkWest Merger included in our consolidated statements of income for 2015 are as follows: (In millions) 2015 Sales and other operating revenues (including consumer excise taxes) $ 120 Income from operations 32 Acquisition of Hess’ Retail Operations and Related Assets On September 30, 2014 , we acquired from Hess Corporation (“Hess”) all of Hess’ retail locations, transport operations and shipper history on various pipelines, including approximately 40 mbpd on Colonial Pipeline, for $2.82 billion . We refer to these assets as “Hess’ Retail Operations and Related Assets.” The transaction was funded with a combination of debt and available cash. The transaction provided for an adjustment for working capital, which was finalized with Hess during the first quarter of 2015, resulting in a $3 million reduction to our total consideration. The purchase price allocation resulted in the recognition of $629 million in goodwill by our Speedway segment. The goodwill primarily relates to the expected benefits of a significantly expanded retail platform that should enable growth in new markets, as well as the potential for higher merchandise sales by utilizing Speedway’s marketing approach at the acquired locations. The goodwill is deductible for tax purposes. We recognized $14 million of acquisition-related costs associated with Hess’ Retail Operations and Related Assets acquisition. These costs were expensed and were included in selling, general and administrative expenses. The amounts of revenue and income from operations associated with Hess’ Retail Operations and Related Assets included in our consolidated statements of income for 2014 are as follows: (In millions) 2014 Sales and other operating revenues (including consumer excise taxes) $ 2,403 Income from operations 113 Unaudited Pro Forma Financial Information The following unaudited pro forma financial information presents consolidated results assuming the MarkWest Merger occurred on January 1, 2014 and the Hess’ Retail Operations and Related Assets acquisition occurred on January 1, 2013. (In millions, except per share data) 2015 2014 Sales and other operating revenues (including consumer excise taxes) $ 73,760 $ 108,605 Net income attributable to MPC 2,825 2,522 Net income attributable to MPC per share – basic $ 5.25 $ 4.42 Net income attributable to MPC per share – diluted 5.21 4.39 The unaudited pro forma financial information includes adjustments to align accounting policies, increased depreciation expense to reflect the fair value of property, plant and equipment, increased amortization expense related to identifiable intangible assets, adjustments to amortize the difference between the fair value and the principal amount of the MarkWest debt assumed by MPLX, adjustments to reflect the change in our limited partner interest in MPLX resulting from the MarkWest Merger, additional interest expense related to financing the acquisition of Hess’ Retail Operations and Related Assets, as well as the related income tax effects. The unaudited pro forma financial information does not give effect to potential synergies that could result from the transactions and is not necessarily indicative of the results of future operations. Acquisition of Biodiesel Facility On April 1, 2014, we purchased a facility in Cincinnati, Ohio from Felda Iffco Sdn Bhd, Malaysia for $40 million . The plant currently produces biodiesel, glycerin and other by-products. The production capacity of the plant is approximately 60 million gallons per year. Neither goodwill nor a gain from a bargain purchase was recognized in conjunction with the biodiesel facility acquisition. Assuming the acquisition of the biodiesel facility in 2014 had been made at the beginning of any period presented, the consolidated pro forma results would not be materially different from reported results. Formation of Travel Plaza Joint Venture In the fourth quarter of 2016, Speedway and Pilot Flying J finalized the formation of a joint venture consisting of 123 travel plazas, primarily in the Southeast United States. The new entity, PFJ Southeast LLC (“PFJ Southeast”), consisted of 41 existing locations contributed by Speedway and 82 locations contributed by Pilot Flying J, all of which carry either the Pilot or Flying J brand and are operated by Pilot Flying J. We did not recognize a gain on the $272 million non-cash contribution of stores to the joint venture since the contribution was that of in-substance real estate. Our non-cash contribution consisted of $203 million of property, plant and equipment, $61 million of goodwill and $8 million of inventory. Marine Investments We currently have indirect ownership interests in two ocean vessel joint ventures with Crowley Maritime Corporation (“Crowley”), which were established to own and operate Jones Act vessels in petroleum product service. We have invested a total of $189 million in these two ventures as described further below. In September 2015, we acquired a 50 percent ownership interest in a joint venture, Crowley Ocean Partners, with Crowley. The joint venture owns and operates four new Jones Act product tankers, three of which are leased to MPC. Two of the vessels were delivered in 2015 and the remaining two were delivered in 2016. We contributed a total of $141 million for the four vessels. In May 2016, MPC and Crowley formed a new ocean vessel joint venture, Crowley Coastal Partners LLC (“Crowley Coastal Partners”), in which MPC has a 50 percent ownership interest. MPC and Crowley each contributed their 50 percent ownership in Crowley Ocean Partners, discussed above, into Crowley Coastal Partners. In addition, we contributed $48 million in cash and Crowley contributed its 100 percent ownership interest in Crowley Blue Water Partners LLC (“Crowley Blue Water Partners”) to Crowley Coastal Partners. Crowley Blue Water Partners is an entity that owns and operates three 750 Series ATB vessels that are leased to MPC. We account for our 50 percent interest in Crowley Coastal Partners as part of our Midstream segment using the equity method of accounting. See Note 6 for information on Crowley Coastal Partners as a VIE and Note 25 for information on our conditional guarantee of the indebtedness of Crowley Ocean Partners and Crowley Blue Water Partners. Investments in Pipeline Companies Bakken Pipeline system On February 15, 2017, MPLX closed on the previously announced transaction to acquire a partial, indirect equity interest in the Dakota Access Pipeline (“DAPL”) and Energy Transfer Crude Oil Company Pipeline (“ETCOP”) projects, collectively referred to as the Bakken Pipeline system, through a joint venture with Enbridge Energy Partners L.P. (“Enbridge Energy Partners”). MPLX contributed $500 million of the $2 billion purchase price paid by the joint venture to acquire a 36.75 percent indirect equity interest in the Bakken Pipeline system from Energy Transfer Partners, L.P. (“ETP”) and Sunoco Logistics Partners, L.P. (“SXL”). MPLX holds, through a subsidiary, a 25 percent interest in the joint venture, which equates to an approximate 9.2 percent indirect equity interest in the Bakken Pipeline system. The Bakken Pipeline system is currently expected to deliver in excess of 470 mbpd of crude oil from the Bakken/Three Forks production area in North Dakota to the Midwest through Patoka, Illinois and ultimately to the Gulf Coast. Furthermore, MPC expects to become a committed shipper on the Bakken Pipeline system under terms of an on-going open season. In connection with closing the transaction with ETP and SXL, Enbridge Energy Partners canceled MPC’s transportation services agreement with respect to the Sandpiper pipeline project and released MPC from paying any termination fee per that agreement. Explorer Pipeline Company In March 2014, we acquired from Chevron Raven Ridge Pipe Line Company an additional seven percent interest in Explorer Pipeline Company (“Explorer”) for $77 million , bringing our ownership interest to 25 percent . As a result of this increase in our ownership, we now account for our investment in Explorer using the equity method of accounting rather than the cost method. The cumulative impact of the change was applied as an adjustment to 2014 retained earnings. Southern Access Extension pipeline project In July 2014, we exercised our option to acquire a 35 percent ownership interest in Enbridge Inc.’s Southern Access Extension (“SAX”) pipeline through our in investment in Illinois Extension Pipeline Company, LLC (“Illinois Extension Pipeline”). This option resulted from our agreement to be the anchor shipper on the SAX pipeline and our commitment to the Sandpiper pipeline project as discussed below. We have contributed $299 million to Illinois Extension Pipeline since project inception. We account for our ownership interest in Illinois Extension Pipeline as an equity method investment. During the construction of the pipeline, our ownership interest in Illinois Extension Pipeline was considered a VIE. Upon completion and start up of the pipeline in December of 2015, a reassessment determined that our investment is no longer considered a VIE. Our investment in the pipeline and our share of its results are included in our Midstream segment. Sandpiper pipeline project In November 2013, we agreed to serve as an anchor shipper for the Sandpiper pipeline project and fund 37.5 percent of the construction costs of the project, which was to become part of Enbridge Energy Partners’ North Dakota System. In exchange for these commitments, we were to earn an approximate 27 percent equity interest in Enbridge Energy Partners’ North Dakota System upon the Sandpiper pipeline being placed into service. We made contributions of $14 million to North Dakota Pipeline Company LLC (“North Dakota Pipeline”) during 2016 and have contributed $301 million since project inception to fund our share of the construction costs for the project. On September 1, 2016, Enbridge Energy Partners announced that its affiliate, North Dakota Pipeline, would withdraw certain pending regulatory applications for its Sandpiper pipeline project and that the project would be deferred indefinitely. These decisions were considered to indicate an impairment of the costs capitalized to date on the project. See Note 17 for information regarding the charge recognized in the third quarter of 2016.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Variable Interest Entities	Variable Interest Entities In addition to MPLX, as described in Note 4 , the following entities are also VIEs. Crowley Coastal Partners In May 2016, Crowley Coastal Partners was formed to own an interest in both Crowley Ocean Partners and Crowley Blue Water Partners. We have determined that Crowley Coastal Partners is a VIE based on the terms of the existing financing arrangements for Crowley Blue Water Partners and Crowley Ocean Partners and the associated debt guarantees by MPC and Crowley. Our maximum exposure to loss at December 31, 2016 was $489 million , which includes our equity method investment in Crowley Coastal Partners and the debt guarantees provided to each of the lenders to Crowley Blue Water Partners and Crowley Ocean Partners. We are not the primary beneficiary of this VIE because we do not have the power to control the activities that significantly influence the economic outcomes of the entity and therefore, do not consolidate the entity. MarkWest Utica EMG On January 1, 2012, MarkWest Utica Operating Company, LLC (“Utica Operating”), a wholly-owned and consolidated subsidiary of MarkWest, and EMG Utica, LLC ("EMG Utica") (together the "Members"), executed agreements to form a joint venture, MarkWest Utica EMG LLC (“MarkWest Utica EMG”), to develop significant natural gas gathering, processing and NGL fractionation, transportation and marketing infrastructure in eastern Ohio. As of December 31, 2016 , MarkWest has a 56 percent legal ownership interest in MarkWest Utica EMG. MarkWest Utica EMG's inability to fund its planned activities without subordinated financial support qualify it as a VIE. Utica Operating is not deemed to be the primary beneficiary due to EMG Utica’s voting rights on significant matters. We account for our ownership interest in MarkWest Utica EMG as an equity method investment. MPLX receives engineering and construction and administrative management fee revenue and reimbursement for other direct personnel costs for operating MarkWest Utica EMG. Our maximum exposure to loss as a result of our involvement with MarkWest Utica EMG includes our equity investment, any additional capital contribution commitments and any operating expenses incurred by the subsidiary operator in excess of compensation received for the performance of the operating services. Our equity investment in MarkWest Utica EMG at December 31, 2016 was $2.22 billion . Ohio Gathering Ohio Gathering Company, L.L.C. (“Ohio Gathering”) is a subsidiary of MarkWest Utica EMG and is engaged in providing natural gas gathering services in the Utica Shale in eastern Ohio. Ohio Gathering is a joint venture between MarkWest Utica EMG and Summit Midstream Partners, LLC. As of December 31, 2016 , we had a 34 percent indirect ownership interest in Ohio Gathering. As this entity is a subsidiary of MarkWest Utica EMG, which is accounted for as an equity method investment, MPLX reports its portion of Ohio Gathering’s net assets as a component of its investment in MarkWest Utica EMG. MPLX receives engineering and construction and administrative management fee revenue and reimbursement for other direct personnel costs for operating Ohio Gathering.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Our related parties included: • Centennial Pipeline LLC (“Centennial”), in which we have a 50 percent noncontrolling interest. Centennial owns a refined products pipeline and storage facility. • Crowley Blue Water Partners, in which we have a 50 percent indirect noncontrolling interest. Crowley Blue Water Partners owns and operates three Jones Act ATB vessels. • Crowley Ocean Partners, in which we have a 50 percent indirect noncontrolling interest. Crowley Ocean Partners owns and operates Jones Act product tankers. • Explorer, in which we have a 25 percent interest. Explorer owns and operates a refined products pipeline. • Illinois Extension Pipeline, in which we have a 35 percent noncontrolling interest. Illinois Extension Pipeline owns and operates a crude oil pipeline. • LOCAP LLC (“LOCAP”), in which we have a 59 percent noncontrolling interest. LOCAP owns and operates a crude oil pipeline. • LOOP LLC (“LOOP”), in which we have a 51 percent noncontrolling interest. LOOP owns and operates the only U.S. deepwater oil port. • MarkWest Utica EMG, in which we have a 56 percent noncontrolling interest. MarkWest Utica EMG is engaged in significant natural gas processing and NGL fractionation, transportation and marketing in the state of Ohio. • Ohio Condensate Company L.L.C. (“Ohio Condensate”), in which we have a 60 percent noncontrolling interest. Ohio Condensate is engaged in wellhead condensate gathering, stabilization, terminalling, transportation and storage within certain defined areas of Ohio. • Ohio Gathering, in which we have a 34 percent indirect noncontrolling interest. Ohio Gathering is a subsidiary of MarkWest Utica EMG providing natural gas gathering service in the Utica Shale region of eastern Ohio. • PFJ Southeast, in which we have a 29 percent noncontrolling interest. PFJ Southeast owns travel plazas primarily in the Southeast United States. • The Andersons Albion Ethanol LLC (“TAAE”), in which we have a 45 percent noncontrolling interest, The Andersons Clymers Ethanol LLC (“TACE”), in which we have a 61 percent noncontrolling interest and The Andersons Marathon Ethanol LLC (“TAME”), in which we have a 67 percent direct and indirect noncontrolling interest. These companies each own and operate an ethanol production facility. • Other equity method investees. We believe that transactions with related parties were conducted on terms comparable to those with unaffiliated parties. Sales to related parties, which are included in “Sales and other operating revenues (including consumer excise taxes)” on the accompanying consolidated statements of income, were as follows: (In millions) 2016 2015 2014 PFJ Southeast $ 56 $ — $ — Other equity method investees 6 6 7 Total $ 62 $ 6 $ 7 Other income from related parties, which is included in “Other income” on the accompanying consolidated statements of income, were as follows: (In millions) 2016 2015 2014 MarkWest Utica EMG $ 16 $ — $ — Ohio Condensate 4 — — Ohio Gathering 15 2 — Other equity method investees 6 2 1 Total $ 41 $ 4 $ 1 Other income from related parties consists primarily of fees received for operating transportation assets for our related parties. Purchases from related parties were as follows: (In millions) 2016 2015 2014 Crowley Blue Water Partners $ 37 $ — $ — Crowley Ocean Partners 52 6 — Explorer 14 20 39 Illinois Extension Pipeline 110 4 — LOCAP 23 23 21 LOOP 59 52 88 TAAE 41 52 79 TACE 59 54 121 TAME 93 87 141 Other equity method investees 21 10 16 Total $ 509 $ 308 $ 505 Related party purchases from Crowley Blue Water Partners and Crowley Ocean Partners consist of leasing marine equipment primarily used to transport refined products. Related party purchases from Explorer consist primarily of refined product transportation costs. Related party purchases from Illinois Extension Pipeline, LOCAP, LOOP and other equity method investees consist primarily of crude oil transportation costs. Related party purchases from TAAE, TACE and TAME consist of ethanol purchases. Receivables from related parties, which are included in “Receivables, less allowance for doubtful accounts” on the accompanying consolidated balance sheets, were as follows: December 31, (In millions) 2016 2015 Centennial $ — $ 1 MarkWest Utica EMG 2 1 Ohio Condensate — 3 Ohio Gathering 2 5 PFJ Southeast 40 — Other equity method investees 1 3 Total $ 45 $ 13 The long-term receivable from related parties, which is included in “Other noncurrent assets” on the accompanying consolidated balance sheet, was $1 million at December 31, 2016 and $1 million at December 31, 2015 . Payables to related parties, which are included in “Accounts payable” on the accompanying consolidated balance sheets, were as follows: December 31, (In millions) 2016 2015 Explorer $ — $ 1 Illinois Extension Pipeline 9 4 LOCAP 2 2 LOOP 6 5 MarkWest Utica EMG 24 19 Ohio Condensate 1 4 TAAE 2 1 TACE 4 2 TAME 4 3 Other equity method investees 1 1 Total $ 53 $ 42

Income per Common Share

Income per Common Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Income per Common Share	Income per Common Share We compute basic earnings per share by dividing net income attributable to MPC by the weighted average number of shares of common stock outstanding. The average number of shares of common stock and per share amounts have been retroactively restated to reflect the two-for-one stock split completed in June 2015. Diluted income per share assumes exercise of certain stock based compensation awards, provided the effect is not anti-dilutive. MPC grants certain incentive compensation awards to employees and non-employee directors that are considered to be participating securities. Due to the presence of participating securities, we have calculated our earnings per share using the two-class method. (In millions, except per share data) 2016 2015 2014 Basic earnings per share: Allocation of earnings: Net income attributable to MPC $ 1,174 $ 2,852 $ 2,524 Income allocated to participating securities 1 4 4 Income available to common stockholders – basic $ 1,173 $ 2,848 $ 2,520 Weighted average common shares outstanding 528 538 570 Basic earnings per share $ 2.22 $ 5.29 $ 4.42 Diluted earnings per share: Allocation of earnings: Net income attributable to MPC $ 1,174 $ 2,852 $ 2,524 Income allocated to participating securities 1 4 4 Income available to common stockholders – diluted $ 1,173 $ 2,848 $ 2,520 Weighted average common shares outstanding 528 538 570 Effect of dilutive securities 2 4 4 Weighted average common shares, including dilutive effect 530 542 574 Diluted earnings per share $ 2.21 $ 5.26 $ 4.39 The following table summarizes the shares that were anti-dilutive, and therefore, were excluded from the diluted share calculation. (In millions) 2016 2015 2014 Shares issued under stock-based compensation plans 3 1 1

Equity

Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Equity	Equity As of December 31, 2016 , we have $2.56 billion of remaining share repurchase 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 affected through Rule 10b5-1 plans. The timing and amount of future repurchases, if any, will depend upon several factors, including market and business conditions, and such repurchases may be discontinued at any time. Total share repurchases were as follows for the respective periods: (In millions, except per share data) 2016 2015 2014 Number of shares repurchased 4 19 49 Cash paid for shares repurchased $ 197 $ 965 $ 2,131 Effective average cost per delivered share $ 41.84 $ 50.31 $ 44.31

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information In the first quarter of 2016, we revised our segment reporting in connection with the contribution of our inland marine business to MPLX. The operating results for our inland marine business and our investment in Crowley Ocean Partners are now reported in our Midstream segment. Previously they were reported as part of our Refining & Marketing segment. Comparable prior period information has been recast to reflect our revised segment presentation. We have three reportable segments: Refining & Marketing; Speedway; 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 refineries in the Gulf Coast and Midwest regions of the United States, purchases ethanol and refined products for resale and distributes refined products through various means, including terminals and trucks that we own or operate. We sell refined products to wholesale marketing customers domestically and internationally, to buyers on the spot market, to our Speedway segment and to independent entrepreneurs who operate Marathon ® retail outlets. • Speedway – sells transportation fuels and convenience merchandise in retail markets in the Midwest, East Coast and Southeast regions of the United States. • Midstream – includes the operations of MPLX and certain other related operations. The Midstream segment gathers, processes and transports natural gas; gathers, transports, fractionates, stores and markets NGLs and transports and stores crude oil and refined products. On December 4, 2015, MPLX completed a merger with MarkWest and its results are included in the Midstream segment. On September 30, 2014, we acquired Hess’ Retail Operations and Related Assets, substantially all of which is part of the Speedway segment. Segment information for periods prior to each acquisition does not include amounts for these operations. See Note 5 . Segment income represents income from operations attributable to the reportable segments. Corporate administrative expenses and costs related to certain non-operating assets are not allocated to the reportable segments. In addition, certain items that affect comparability (as determined by the chief operating decision maker) are not allocated to the reportable segments. (In millions) Refining & Marketing Speedway Midstream Total Year Ended December 31, 2016 Revenues: Customer $ 43,228 $ 18,283 $ 1,828 $ 63,339 Intersegment (a) 10,589 3 808 11,400 Segment revenues $ 53,817 $ 18,286 $ 2,636 $ 74,739 Segment income from operations (b)(c) $ 1,543 $ 734 $ 871 $ 3,148 Income from equity method investments (d) 24 5 142 171 Depreciation and amortization (d) 1,092 273 576 1,941 Capital expenditures and investments (e) 1,101 303 1,521 2,925 (In millions) Refining & Marketing Speedway Midstream Total Year Ended December 31, 2015 Revenues: Customer $ 52,174 $ 19,690 $ 187 $ 72,051 Intersegment (a) 12,024 3 777 12,804 Segment revenues $ 64,198 $ 19,693 $ 964 $ 84,855 Segment income from operations (b)(c) $ 4,086 $ 673 $ 380 $ 5,139 Income from equity method investments 26 — 62 88 Depreciation and amortization (d) 1,052 254 144 1,450 Capital expenditures and investments (e)(f) 1,045 501 14,545 16,091 (In millions) Refining & Marketing Speedway Midstream Total Year Ended December 31, 2014 Revenues: Customer $ 80,821 $ 16,927 $ 71 $ 97,819 Intersegment (a) 10,912 5 753 11,670 Segment revenues $ 91,733 $ 16,932 $ 824 $ 109,489 Segment income from operations (b) $ 3,538 $ 544 $ 342 $ 4,424 Income from equity method investments 96 — 57 153 Depreciation and amortization (d) 1,020 152 102 1,274 Capital expenditures and investments (e)(g) 1,043 2,981 604 4,628 (a) Management believes intersegment transactions were conducted under terms comparable to those with unaffiliated parties. (b) Included in the Midstream segment for 2016 , 2015 and 2014 are $11 million , $20 million and $19 million , respectively, of corporate overhead expenses attributable to MPLX. The remaining corporate overhead expenses are not currently allocated to other segments, but instead are reported in corporate and other unallocated items. Also included in the Midstream segment for 2015 are $36 million of transaction costs related to the MarkWest Merger. (c) In 2016, the Refining & Marketing and Speedway segments include an inventory LCM benefit of $345 million and $25 million , respectively. In 2015, the Refining & Marketing and Speedway segments include an inventory LCM charge of $345 million and $25 million , respectively. (d) Differences between segment totals and MPC totals represent amounts related to unallocated items and are included in “Items not allocated to segments” in the reconciliation below. (e) Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates. (f) The Midstream segment includes $13.85 billion for the MarkWest Merger. See Note 5 . (g) The Speedway and Refining & Marketing segments include $2.66 billion and $52 million , respectively, for the acquisition of Hess’ Retail Operations and Related Assets. See Note 5 . The following reconciles segment income from operations to income before income taxes as reported in the consolidated statements of income: (In millions) 2016 2015 2014 Segment income from operations $ 3,148 $ 5,139 $ 4,424 Items not allocated to segments: Corporate and other unallocated items (a) (277 ) (299 ) (277 ) Pension settlement expenses (b) (7 ) (4 ) (96 ) Impairments (c) (486 ) (144 ) — Net interest and other financial income (costs) (556 ) (318 ) (216 ) Income before income taxes $ 1,822 $ 4,374 $ 3,835 (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, which are included in the Midstream segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments. (b) See Note 22 . (c) 2016 includes impairments of goodwill and equity method investments. 2015 relates to the cancellation of the ROUX project at our Garyville refinery. See Notes 15 , 16 and 17 . The following reconciles segment capital expenditures and investments to total capital expenditures: (In millions) 2016 2015 2014 Segment capital expenditures and investments $ 2,925 $ 16,091 $ 4,628 Less investments in equity method investees (a) 431 2,788 413 Plus items not allocated to segments: Corporate and Other 81 155 83 Capitalized interest 63 37 27 Total capital expenditures (b) $ 2,638 $ 13,495 $ 4,325 (a) 2016 includes an adjustment of $143 million to the fair value of equity method investments acquired in connection with the MarkWest Merger. 2015 includes $2.46 billion for the MarkWest Merger. See Note 5 . (b) Capital expenditures include changes in capital accruals. See Note 20 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows. The following reconciles total segment customer revenues to sales and other operating revenues (including consumer excise taxes) as reported in the consolidated statements of income: (In millions) 2016 2015 2014 Customer revenues $ 63,339 $ 72,051 $ 97,819 Corporate and other unallocated items — — (2 ) Sales and other operating revenues (including consumer excise taxes) $ 63,339 $ 72,051 $ 97,817 Revenues by product line were: (In millions) 2016 2015 2014 Refined products $ 54,511 $ 63,744 $ 90,702 Merchandise 5,297 5,188 3,817 Crude oil and refinery feedstocks 2,038 2,718 2,917 Service, transportation and other 1,493 401 381 Sales and other operating revenues (including consumer excise taxes) $ 63,339 $ 72,051 $ 97,817 No single customer accounted for more than 10 percent of annual revenues for the years ended December 31, 2016 , 2015 and 2014 . We do not have significant operations in foreign countries. Therefore, revenues in foreign countries and long-lived assets located in foreign countries, including property, plant and equipment and investments, are not material to our operations. Total assets by reportable segment were: December 31, (In millions) 2016 2015 Refining & Marketing $ 18,039 $ 17,379 Speedway 5,426 5,349 Midstream 18,078 17,462 Corporate and Other 2,870 2,925 Total consolidated assets $ 44,413 $ 43,115

Other Items

Other Items	12 Months Ended
	Dec. 31, 2016
Other Income and Expenses [Abstract]
Other Items	Other Items Net interest and other financial income (costs) was: (In millions) 2016 2015 2014 Interest income $ 6 $ 6 $ 7 Interest expense (a) (602 ) (325 ) (229 ) Interest capitalized 64 37 27 Loss on extinguishment of debt — (5 ) — Other financial costs (b) (24 ) (31 ) (21 ) Net interest and other financial income (costs) $ (556 ) $ (318 ) $ (216 ) (a) 2016 and 2015 includes $44 million and $1 million , respectively, for the amortization of the discount related to the difference between the fair value and the principal amount of the assumed MarkWest debt. (b) 2015 includes $6 million of transaction costs related to the MarkWest Merger.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax provisions (benefits) were: 2016 2015 2014 (In millions) Current Deferred Total Current Deferred Total Current Deferred Total Federal $ 189 $ 336 $ 525 $ 1,210 $ 134 $ 1,344 $ 1,382 $ (199 ) $ 1,183 State and local 27 57 84 152 9 161 135 (37 ) 98 Foreign (1 ) 1 — 10 (9 ) 1 5 (6 ) (1 ) Total $ 215 $ 394 $ 609 $ 1,372 $ 134 $ 1,506 $ 1,522 $ (242 ) $ 1,280 A reconciliation of the federal statutory income tax rate ( 35 percent ) applied to income before income taxes to the provision for income taxes follows: 2016 2015 2014 Statutory rate applied to income before income taxes 35 % 35 % 35 % State and local income taxes, net of federal income tax effects 3 2 2 Domestic manufacturing deduction (1 ) (2 ) (2 ) Noncontrolling interests (1 ) — — Biodiesel excise tax credit (1 ) (1 ) — Other (2 ) — (2 ) Provision for income taxes 33 % 34 % 33 % Deferred tax assets and liabilities resulted from the following: December 31, (In millions) 2016 2015 Deferred tax assets: Employee benefits $ 578 $ 631 Environmental 34 44 Net operating loss carryforwards 23 73 Other 58 73 Total deferred tax assets 693 821 Deferred tax liabilities: Property, plant and equipment 2,591 2,512 Inventories 707 579 Investments in subsidiaries and affiliates 1,145 909 Other 94 89 Total deferred tax liabilities 4,537 4,089 Net deferred tax liabilities $ 3,844 $ 3,268 Net deferred tax liabilities were classified in the consolidated balance sheets as follows: December 31, (In millions) 2016 2015 Assets: Other noncurrent assets $ 17 $ 17 Liabilities: Deferred income taxes 3,861 3,285 Net deferred tax liabilities $ 3,844 $ 3,268 Tax carryforwards – At December 31, 2016 and 2015 , federal operating loss carryforwards were $18 million and $66 million , respectively, which expire in 2022 through 2036 . As of December 31, 2016 and 2015 , state and local operating loss carryforwards were $8 million and $10 million , respectively, which expire in 2017 through 2036 . The decrease in both the federal and state loss carryforwards was due to the utilization of loss carryforwards as a part of the reorganization transactions which simplified the MPLX ownership structure as discussed in Note 4 . Valuation allowances – As of December 31, 2016 and 2015 , $10 million and $5 million of valuation allowances were recognized primarily due to the expected realizability of foreign tax credits and based on estimates of future financial income and expected realizability of state and local tax operating losses. MPC is continuously undergoing examination of its U.S. federal income tax returns by the Internal Revenue Service. Such audits have been completed through the 2009 tax year. We believe adequate provision has been made for federal income taxes and interest which may become payable for years not yet settled. Further, we are routinely involved in U.S. state income tax audits. We believe all other audits will be resolved with the amounts paid and/or provided for these liabilities. As of December 31, 2016 , our income tax returns remain subject to examination in the following major tax jurisdictions for the tax years indicated: United States Federal 2010 - 2015 States 2008 - 2015 During the first quarter of 2016, MPC’s deferred tax liabilities increased $115 million and additional paid-in capital decreased by the same amount for an out of period adjustment to update the preliminary tax effects recorded in 2015 related to the MarkWest Merger. The impact of the out of period adjustment was not material to the consolidated balance sheet as of December 31, 2015. The following table summarizes the activity in unrecognized tax benefits: (In millions) 2016 2015 2014 January 1 balance $ 12 $ 12 $ 13 Additions for tax positions of prior years 6 — 7 Reductions for tax positions of prior years (10 ) — (10 ) Settlements (1 ) — 2 December 31 balance $ 7 $ 12 $ 12 If the unrecognized tax benefits as of December 31, 2016 were recognized, $2 million would affect our effective income tax rate. There were $1 million of uncertain tax positions as of December 31, 2016 for which it is reasonably possible that the amount of unrecognized tax benefits would significantly decrease during the next twelve months. Interest and penalties related to income taxes are recorded as part of the provision for income taxes. Such interest and penalties were net expenses (benefits) of $(5) million , $3 million and less than $1 million in 2016 , 2015 and 2014 , respectively. As of December 31, 2016 and 2015 , $13 million and $18 million of interest and penalties were accrued related to income taxes.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories December 31, (In millions) 2016 2015 Crude oil and refinery feedstocks $ 2,208 $ 2,180 Refined products 2,810 2,804 Materials and supplies 485 438 Merchandise 153 173 Lower of cost or market reserve — (370 ) Total $ 5,656 $ 5,225 The LIFO method accounted for 91 percent of total inventory value at both December 31, 2016 and 2015 . Inventories are carried at the lower of cost or market value. Costs of crude oil, refinery feedstocks and refined products are aggregated on a consolidated basis for purposes of assessing if the LIFO cost basis of these inventories may have to be written down to market values. As of December 31, 2015, costs of inventories exceeded market value by $370 million resulting in a charge to cost of revenues to establish an LCM inventory valuation reserve. During 2016, market prices for these inventories increased and the market value of these inventories exceeded their cost basis resulting in a reversal of the LCM inventory reserve and a $370 million benefit to cost of revenues. At December 31, 2016 , current acquisition costs of inventories were estimated to exceed the LIFO inventory value by $308 million . There were no material liquidations of LIFO inventories in 2016 . In the second quarter of 2016, we had recognized the effects of an interim liquidation of our refined products inventories which we did not expect to reinstate by year end resulting in a pre-tax charge of approximately $54 million to income. Due to the annual build of refined products inventories, in the fourth quarter of 2016 , we recognized the effects of annual builds in our refined products and crude inventories which had the effect of reversing the second quarter charge. During 2015 , we recorded LIFO liquidations caused by permanently decreased levels in crude oil and refined products inventory levels. Cost of revenues increased and income from operations decreased by $78 million for the year ended December 31, 2015 due to these LIFO liquidations. There were no liquidations of LIFO inventories in 2014 .

Equity Method Investments

Equity Method Investments	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	Equity Method Investments Ownership as of Carrying value at December 31, December 31, (In millions) 2016 2016 2015 Centennial 50% $ 35 $ 37 Centrahoma Processing LLC 40% 104 111 Crowley Coastal Partners 50% 184 — Crowley Ocean Partners (a) 50% — 72 Explorer 25% 94 91 Illinois Extension Pipeline 35% 293 267 LOCAP 59% 22 22 LOOP 51% 277 243 MarkWest Utica EMG 56% 2,224 2,160 North Dakota Pipeline (b) 38% 30 287 Ohio Condensate (b) 60% 10 101 PFJ Southeast (c) 29% 283 — TAAE 45% 33 27 TACE 61% 33 49 TAEI 34% 15 18 TAME (d) 50% 18 27 Other MPLX investments 129 86 Other 43 24 Total $ 3,827 $ 3,622 (a) Crowley Ocean Partners merged into Crowley Coastal Partners in 2016. (b) During 2016, we recorded an impairment charge of $267 million related to our investment in North Dakota Pipeline and an impairment charge of $89 million related to our investment in Ohio Condensate. See Note 17 for additional information. (c) This joint venture with Pilot Flying J was formed in 2016. See Note 5 . (d) Excludes TAEI’s investment in TAME. Summarized financial information for equity method investees is as follows: (In millions) 2016 2015 2014 Income statement data: Revenues and other income $ 2,421 $ 1,390 $ 1,430 Income (loss) from operations (116 ) 332 379 Net income (loss) (250 ) 239 316 Balance sheet data – December 31: Current assets $ 711 $ 906 Noncurrent assets 8,170 6,418 Current liabilities 884 468 Noncurrent liabilities 1,462 1,130 As of December 31, 2016 , the carrying value of our equity method investments was $1.21 billion higher than the underlying net assets of investees. This basis difference is being amortized or accreted into net income over the remaining estimated useful lives of the underlying net assets, except for $553 million of excess related to goodwill. Centennial experienced a significant reduction in shipment volumes in the second half of 2011 that has continued through 2016. At December 31, 2016, Centennial was not shipping product. As a result, we continued to evaluate the carrying value of our equity investment in Centennial. We concluded that no impairment was required given our assessment of its fair value based on market participant assumptions for various potential uses and future cash flows of Centennial’s assets. If market conditions were to change and the owners of Centennial are unable to find an alternative use for the assets, there could be a future impairment of our Centennial interest. As of December 31, 2016 , our equity investment in Centennial was $35 million and we had a $29 million guarantee associated with 50 percent of Centennial’s outstanding debt. See Note 25 for additional information on the debt guarantee. Dividends and partnership distributions received from equity method investees (excluding distributions that represented a return of capital previously contributed) were $291 million , $113 million and $170 million in 2016 , 2015 and 2014 .

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment (In millions) Estimated Useful Lives December 31, 2016 2015 Refining & Marketing 2 - 30 years $ 19,447 $ 18,396 Speedway 4 - 25 years 5,078 5,067 Midstream 3 - 42 years 12,664 11,379 Corporate and Other 4 - 40 years 817 762 Total 38,006 35,604 Less accumulated depreciation 12,241 10,440 Property, plant and equipment, net $ 25,765 $ 25,164 Property, plant and equipment includes gross assets acquired under capital leases of $505 million and $511 million at December 31, 2016 and 2015 , respectively, with related amounts in accumulated depreciation of $202 million and $176 million at December 31, 2016 and 2015 . Property, plant and equipment includes construction in progress of $2.02 billion and $2.26 billion at December 31, 2016 and 2015 , respectively, which primarily relates to capital projects at our refineries and midstream facilities. In the third quarter of 2015, we decided to cancel the ROUX project at our Garyville, Louisiana refinery due to the implications of current market conditions. The project was intended to increase margins by upgrading residual fuel to ultra-low sulfur diesel and gas oil. As a result, we recorded a $144 million impairment charge to write off the costs incurred through September 30, 2015 on the project. This impairment charge is included in “Impairment expense” on the accompanying consolidated statements of income.

Goodwill and Intangibles

Goodwill and Intangibles	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill and Intangibles Goodwill Goodwill is tested for impairment on an annual basis and when events or changes in circumstances indicate the fair value of a reporting unit with goodwill has been reduced below the carrying value of the net assets of the reporting unit. In 2016 , we recorded an impairment of goodwill as outlined below based on an interim impairment analysis. There was no impairment required based on our subsequent annual test of goodwill in 2016. In 2015 , no impairment was required based on our annual test. During the first quarter of 2016, MPLX, our consolidated subsidiary, determined that an interim impairment analysis of the goodwill recorded in connection with the MarkWest Merger was necessary based on consideration of a number of first quarter events and circumstances, including i) continued deterioration of near-term commodity prices as well as longer term pricing trends, ii) recent guidance on reductions to forecasted capital spending, the slowing of drilling activity and the resulting reduced production growth forecasts released or communicated by MPLX’s producer customers and iii) increases in the cost of capital. The combination of these factors was considered to be a triggering event requiring an interim impairment test. Based on the first step of the interim goodwill impairment analysis, the fair value for three of the reporting units to which goodwill was assigned in connection with the MarkWest Merger was less than their respective carrying value. In step two of the impairment analysis, the implied fair values of the goodwill were compared to the carrying values within those reporting units. Based on this assessment, it was determined that goodwill was impaired in two of the reporting units. Accordingly, MPLX recorded an impairment charge of approximately $129 million in the first quarter of 2016. In the second quarter of 2016, MPLX completed its purchase price allocation, which resulted in an additional $1 million of impairment expense that would have been recorded in the first quarter of 2016 had the purchase price allocation been completed as of that date. This adjustment to the impairment expense was the result of completing an evaluation of the deferred tax liabilities associated with the MarkWest Merger and their impact on the resulting goodwill that was recognized. The fair value of the reporting units for the interim goodwill impairment analysis was determined based on applying the discounted cash flow method, which is an income approach, and the guideline public company method, which is a market approach. The discounted cash flow fair value estimate was based on known or knowable information at the interim measurement date. The significant assumptions that were used to develop the estimates of the fair values under the discounted cash flow method include management’s best estimates of the expected future results and discount rates, which ranged from 10.5 percent to 11.5 percent . Fair value determinations require considerable judgment and are sensitive to changes in underlying assumptions and factors. As a result, there can be no assurance that the estimates and assumptions made for purposes of the interim goodwill impairment test will prove to be an accurate prediction of the future. The changes in the carrying amount of goodwill for 2016 and 2015 were as follows: (In millions) Refining & Marketing Speedway Midstream Total Balance at January 1, 2015 $ 539 $ 854 $ 173 $ 1,566 Acquisitions (a) — — 2,454 2,454 Disposition — (1 ) — (1 ) Balance at December 31, 2015 $ 539 $ 853 $ 2,627 $ 4,019 Purchase price allocation adjustments (a) — — (241 ) (241 ) Disposition (b) — (61 ) — (61 ) Impairment — — (130 ) (130 ) Balance at December 31, 2016 $ 539 $ 792 $ 2,256 $ 3,587 (a) See Note 5 for information on the acquisitions and purchase price allocation adjustments. (b) Goodwill associated with our former Speedway travel plaza locations that are now part of the PFJ Southeast joint venture. The amount was included in the initial basis for our equity method investment in the joint venture. Intangible Assets Our intangible assets as of December 31, 2016 and 2015 are as follows: (In millions) Refining & Marketing Speedway Midstream Total Balance at December 31, 2016 Customer contracts and relationships $ 102 $ 1 $ 533 $ 636 Royalty agreements 128 — — 128 Favorable lease contract terms 1 57 — 58 Other (a) 27 75 — 102 Gross $ 258 $ 133 $ 533 $ 924 Accumulated amortization (123 ) (35 ) (41 ) (199 ) Net $ 135 $ 98 $ 492 $ 725 Balance at December 31, 2015 Customer contracts and relationships $ 91 $ 1 $ 468 $ 560 Royalty agreements 122 — — 122 Favorable lease contract terms 1 70 — 71 Other (a) 28 75 — 103 Gross $ 242 $ 146 $ 468 $ 856 Accumulated amortization (104 ) (31 ) (2 ) (137 ) Net $ 138 $ 115 $ 466 $ 719 (a) The Refining & Marketing and Speedway segments include unamortized intangible assets of $3 million and $46 million , respectively, which are primarily trademarks. Amortization expense for 2016 and 2015 was $50 million and $29 million , respectively. Estimated future amortization expense related to the intangible assets at December 31, 2016 is as follows: (In millions) 2017 $ 49 2018 49 2019 49 2020 48 2021 46

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 and 2015 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. December 31, 2016 Fair Value Hierarchy (In millions) Level 1 Level 2 Level 3 Netting and Collateral (a) Net Carrying Value on Balance Sheet (b) Collateral Pledged Not Offset Commodity derivative instruments, assets $ 688 $ — $ — $ (688 ) $ — $ 126 Other assets 2 — — N/A 2 — Total assets at fair value $ 690 $ — $ — $ (688 ) $ 2 $ 126 Commodity derivative instruments, liabilities $ 712 $ — $ 6 $ (712 ) $ 6 $ — Embedded derivatives in commodity contracts (c) — — 54 — 54 — Contingent consideration, liability (d) — — 130 N/A 130 — Total liabilities at fair value $ 712 $ — $ 190 $ (712 ) $ 190 $ — December 31, 2015 Fair Value Hierarchy (In millions) Level 1 Level 2 Level 3 Netting and Collateral (a) Net Carrying Value on Balance Sheet (b) Collateral Pledged Not Offset Commodity derivative instruments, assets $ 104 $ 2 $ 7 $ (62 ) $ 51 $ — Other assets 2 — — N/A 2 — Total assets at fair value $ 106 $ 2 $ 7 $ (62 ) $ 53 $ — Commodity derivative instruments, liabilities $ 39 $ — $ — $ (39 ) $ — $ — Embedded derivatives in commodity contracts (c) — — 32 $ — 32 — Contingent consideration, liability (d) — — 317 N/A 317 — Total liabilities at fair value $ 39 $ — $ 349 $ (39 ) $ 349 $ — (a) Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of December 31, 2016 , cash collateral of $24 million was netted with mark-to-market derivative liabilities. As of December 31, 2015 , cash collateral of $23 million was netted with mark-to-market derivative assets. (b) We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet. (c) Includes $13 million and $5 million classified as current as of December 31, 2016 and 2015 , respectively. (d) Includes $130 million and $196 million classified as current as of December 31, 2016 and 2015 , respectively. Commodity derivatives in Level 1 are exchange-traded contracts for crude oil and refined products measured at fair value with a market approach using the close-of-day settlement prices for the market. Commodity derivatives are covered under master netting agreements with an unconditional right to offset. Collateral deposits in futures commission merchant accounts covered by master netting agreements related to Level 1 commodity derivatives are classified as Level 1 in the fair value hierarchy. Commodity derivatives in Level 2 include crude oil and natural gas swap contracts and are measured at fair value with a market approach. The valuations are based on the appropriate commodity prices and contain no significant unobservable inputs. LIBO Rates are an observable input for the measurement of these derivative contracts. The measurements for commodity contracts contain observable inputs in the form of forward prices based on WTI crude oil prices; and Columbia Appalachia, Henry Hub, PEPL and Houston Ship Channel natural gas prices. Level 3 instruments include 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 December 31, 2016 used significant unobservable inputs including: (1) NGL prices interpolated and extrapolated due to inactive markets ranging from $0.28 to $1.27 per gallon and (2) the probability of renewal of 50 percent for the first five -year term and 75 percent for the second five -year term of the 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. The forward prices for the individual NGL products generally increase or decrease in a positive correlation with one another. Increases or decreases in forward NGL prices result in an increase or decrease in the fair value of the embedded derivative. An increase in the probability of renewal would result in an increase in the fair value of the related embedded derivative liability. The contingent consideration represents the fair value as of December 31, 2016 and 2015 of the remaining amount we expect to pay to BP related to the earnout provision associated with our 2013 acquisition of BP’s refinery in Texas City, Texas and related logistics and marketing assets. We refer to these assets as the “Galveston Bay Refinery and Related Assets”. The fair value of the remaining contingent consideration was estimated using an income approach and is therefore a Level 3 liability. The amount of cash to be paid under the arrangement is based on both a market-based crack spread and refinery throughput volumes for the months during which the earnout applies, as well as established thresholds that cap the annual and total payment. The earnout payment cannot exceed $250 million per year for the last three years of the arrangement, with the total cumulative payment capped at $700 million over the six-year period commencing in 2014. Any excess or shortfall from the annual cap for a current year’s earnout calculation will not affect subsequent years’ calculations. The fair value calculation used significant unobservable inputs including: (1) an estimate of forecasted monthly refinery throughput volumes; (2) an internal and external monthly crack spread forecast of approximately $13 per barrel; and (3) a range of risk-adjusted discount rates from five percent to 10 percent . An increase or decrease in forecasts for the crack spread or refinery throughput volumes may result in a corresponding increase or decrease in the fair value of the contingent consideration liability. Increases to the fair value as a result of increasing forecasts for both of these unobservable inputs, however, are limited as the earnout payment is subject to annual caps. An increase or decrease in the discount rate may result in a decrease or increase to the fair value of the contingent consideration liability, respectively. The fair value of the contingent consideration liability is reassessed each quarter, with changes in fair value recorded in cost of revenues. Through December 31, 2016 , we have paid BP approximately $569 million in total leaving $131 million remaining under the total cap of $700 million . The following is a reconciliation of the net beginning and ending balances recorded for net assets and liabilities classified as Level 3 in the fair value hierarchy. (In millions) 2016 2015 2014 Beginning balance $ 342 $ 478 $ 625 Contingent consideration payment (a) (200 ) (189 ) (180 ) Net derivative positions assumed - MarkWest Merger — 31 — Unrealized and realized losses included in net income 55 20 33 Settlements of derivative instruments (7 ) 2 — Ending balance $ 190 $ 342 $ 478 The amount of total (gains) losses for the period included in earnings attributable to the change in unrealized (gains) losses relating to assets still held at the end of period: Derivative instruments $ 32 $ (7 ) $ — Contingent consideration agreement 13 28 33 Total $ 45 $ 21 $ 33 (a) On the consolidated statements of cash flows for 2016, 2015 and 2014, $164 million , $175 million and $172 million , respectively, of the contingent earnout payment to BP was included as a financing activity with the remainder included as an operating activity. See Note 18 for the income statement impacts of our derivative instruments. Fair Values – Nonrecurring The following table shows the values of assets, by major category, measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition. Year Ended December 31, 2016 2015 2014 (In millions) Fair Value Impairment Fair Value Impairment Fair Value Impairment Equity method investments $ 42 $ 356 $ — $ — $ — $ — Goodwill — 130 — — — — Property, plant and equipment, net — — — 144 — — Other noncurrent assets — — — — — 11 During the third quarter of 2016, Enbridge Energy Partners announced that its affiliate, North Dakota Pipeline, would withdraw certain pending regulatory applications for the Sandpiper pipeline project and that the project would be deferred indefinitely. These decisions were considered to indicate an impairment of the costs capitalized to date on the project. As the operator of North Dakota Pipeline and the entity responsible for maintaining its financial records, Enbridge completed a fixed asset impairment analysis as of August 31, 2016, in accordance with ASC Topic 360. Based on the estimated liquidation value of the fixed assets, an impairment charge was recorded by North Dakota Pipeline. Based on our 37.5 percent ownership of North Dakota Pipeline, we recognized approximately $267 million of this charge in the third quarter of 2016 through “Income (loss) from equity method investments” on the accompanying consolidated statements of income, which impaired virtually all of our $301 million investment in the project. Also, in accordance with ASC Topic 323, we completed an assessment to determine any additional equity method impairment charge to be recorded on our consolidated financial statements resulting from an other-than-temporary impairment. The result of this analysis indicated no additional charge was required to be recorded. The fixed assets of North Dakota Pipeline related to the Sandpiper pipeline project consist primarily of project management and engineering costs, pipe, valves, motors and other equipment, land and easements. The fair value of fixed assets was estimated based on a market approach using the estimated price that would be received to sell pipe, land and other related equipment in its current condition, considering the current market conditions for sale of these assets and length of disposal period. The valuation considered a range of potential selling prices from various alternatives that could be used to dispose of these assets. As such, the fair value of the North Dakota Pipeline equity method investment and its underlying assets represents a Level 3 measurement. As a result, actual results may differ from the estimates and assumptions made for purposes of this impairment analysis. North Dakota Pipeline expects to dispose of these assets through orderly transactions. During the second quarter of 2016, forecasts for Ohio Condensate, an equity method investment, were reduced in line with updated forecasts for customer requirements. As the operator of that entity responsible for maintaining its financial records, we completed a fixed asset impairment analysis as of June 30, 2016, in accordance with ASC Topic 360, to determine the potential fixed asset impairment charge. The resulting fixed asset impairment charge recorded within Ohio Condensate’s financial statements was $96 million . Based on our 60 percent ownership of Ohio Condensate, approximately $58 million was recorded in the second quarter of 2016 in “Income (loss) from equity method investments” on the accompanying consolidated statements of income. Our investment in Ohio Condensate, which was established at fair value in connection with the MarkWest Merger, exceeded its proportionate share of the underlying net assets. Therefore, in conjunction with the ASC Topic 360 impairment analysis, we completed an equity method impairment analysis in accordance with ASC Topic 323 to determine the potential additional equity method impairment charge to be recorded on our consolidated financial statements resulting from an other-than-temporary impairment. As a result, an additional impairment charge of approximately $31 million was recorded in the second quarter of 2016 in “Income (loss) from equity method investments” on the accompanying consolidated statements of income, which eliminated the basis differential established in connection with the MarkWest Merger. The fair value of Ohio Condensate and its underlying assets was determined based upon applying the discounted cash flow method, which is an income approach, and the guideline public company method, which is a market approach. The discounted cash flow fair value estimate is based on known or knowable information at the interim measurement date. The significant assumptions that were used to develop the estimate of the fair value under the discounted cash flow method include management’s best estimates of the expected future results using a probability weighted average set of cash flow forecasts and a discount rate of 11.2 percent . Fair value determinations require considerable judgment and are sensitive to changes in underlying assumptions and factors. As such, the fair value of the Ohio Condensate equity method investment and its underlying assets represents a Level 3 measurement. As a result, actual results may differ from the estimates and assumptions made for purposes of this impairment analysis. See Note 16 for additional information on the goodwill impairment. In the third quarter of 2015, we decided to cancel the ROUX project at our Garyville refinery. The work completed on the project through September 30, 2015 had no alternate use or net salvage value; therefore, we fully impaired the $144 million of cost capitalized for the project through that date. The fair value of our investment in the project was determined using an income approach and is classified as Level 3. Based on the financial and operational status of a company in which we have an interest, we fully impaired our $11 million investment in that company in 2014. Our investment in this company was accounted for using the cost method and was included in our Refining & Marketing segment. The impairment charge is included in “Other income” on the accompanying consolidated statements of income. The fair value of our investment in this cost company was measured using an income approach. This measurement is classified as Level 3. Fair Values – Reported The following table summarizes financial instruments on the basis of their nature, characteristics and risk at December 31, 2016 and 2015 , excluding the derivative financial instruments and contingent consideration reported above. December 31, 2016 2015 (In millions) Fair Value Carrying Value Fair Value Carrying Value Financial assets: Investments $ 25 $ 2 $ 33 $ 2 Other 21 21 35 33 Total financial assets $ 46 $ 23 $ 68 $ 35 Financial liabilities: Long-term debt (a) $ 10,892 $ 10,297 $ 11,366 $ 11,628 Deferred credits and other liabilities 121 109 136 135 Total financial liabilities $ 11,013 $ 10,406 $ 11,502 $ 11,763 (a) Excludes capital leases and debt issuance costs, however, includes amount classified as debt due within one year. Our current assets and liabilities include financial instruments, the most significant of which are trade accounts receivable and payables. We believe the carrying values of our current assets and liabilities approximate fair value. Our fair value assessment incorporates a variety of considerations, including (1) the short-term duration of the instruments, (2) our investment-grade credit rating and (3) our historical incurrence of and expected future insignificance of bad debt expense, which includes an evaluation of counterparty credit risk. Fair values of our financial assets included in investments and other financial assets and of our financial liabilities included in deferred credits and other liabilities are measured primarily using an income approach and most inputs are internally generated, which results in a Level 3 classification. Estimated future cash flows are discounted using a rate deemed appropriate to obtain the fair value. Other financial assets primarily consist of environmental remediation receivables. Deferred credits and other liabilities primarily consist of a liability resulting from a financing arrangement for the construction of the steam methane reformer (“SMR”) at the Javelina gas processing and fractionation complex in Corpus Christi, Texas, insurance liabilities and environmental remediation liabilities. Fair value of fixed-rate long-term debt is measured using a market approach, based upon the average of quotes for our debt from major financial institutions and a third-party valuation service. Because these quotes cannot be independently verified to the market, they are considered Level 3 inputs. Fair value of variable-rate long-term debt approximates the carrying value.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2016
Summary of Derivative Instruments [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 17 . See Note 2 for a discussion of the types of derivatives we use and the reasons for them. We do not designate any of our commodity derivative instruments as hedges for accounting purposes. Our interest rate derivative instruments that were terminated in 2012 had been designated as fair value accounting hedges. The following table presents the gross fair values of derivative instruments, excluding cash collateral, and where they appear on the consolidated balance sheets as of December 31, 2016 and 2015 : (In millions) December 31, 2016 Balance Sheet Location Asset Liability Commodity derivatives Other current assets $ 688 $ 712 Other current liabilities (a) — 13 Deferred credits and other liabilities (a) — 47 (In millions) December 31, 2015 Balance Sheet Location Asset Liability Commodity derivatives Other current assets $ 113 $ 39 Other current liabilities (a) — 5 Deferred credits and other liabilities (a) — 27 (a) Includes embedded derivatives. Derivatives not Designated as Accounting Hedges 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) sale of NGLs, (6) the purchase of natural gas and (7) purchase of electricity. The table below summarizes open commodity derivative contracts for crude oil and refined products as of December 31, 2016 . Position Total Barrels (In thousands) Crude Oil (a) Exchange-traded Long 53,028 Exchange-traded Short (52,373 ) OTC Short (37 ) (a ) 98.7 percent of the exchange-traded contracts expire in the first quarter of 2017 . Position MMbtu Natural Gas OTC Long 297,017 Position Total Gallons (In thousands) Refined Products (a) Exchange-traded Long 196,434 Exchange-traded Short (221,970 ) OTC Short (64,212 ) (a ) 100 percent of the exchange-traded contracts expire in the first quarter of 2017 . The following table summarizes the effect of all commodity derivative instruments in our consolidated statements of income: (In millions) Gain (Loss) Income Statement Location 2016 2015 2014 Sales and other operating revenues $ (13 ) $ 19 $ 37 Cost of revenues (167 ) 294 456 Total $ (180 ) $ 313 $ 493

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt	Debt Our outstanding borrowings at December 31, 2016 and 2015 consisted of the following: December 31, (In millions) 2016 2015 Marathon Petroleum Corporation: Commercial paper $ — $ — 364-day bank revolving credit facility due July 2017 — — Trade receivables securitization facility due July 2019 — — Bank revolving credit facility due 2020 — — Term loan agreement due 2019 200 700 Senior notes, 2.700% due December 2018 600 600 Senior notes, 3.400% due December 2020 650 650 Senior notes, 5.125% due March 2021 1,000 1,000 Senior notes, 3.625%, due September 2024 750 750 Senior notes, 6.500%, due March 2041 1,250 1,250 Senior notes, 4.750%, due September 2044 800 800 Senior notes, 5.850% due December 2045 250 250 Senior notes, 5.000%, due September 2054 400 400 MPLX LP: MPLX term loan facility due 2019 250 250 MPLX bank revolving credit facility due 2020 — 877 MPLX senior notes, 5.500%, due February 2023 710 710 MPLX senior notes, 4.500%, due July 2023 989 989 MPLX senior notes, 4.875%, due December 2024 1,149 1,149 MPLX senior notes, 4.000%, due February 2025 500 500 MPLX senior notes, 4.875%, due June 2025 1,189 1,189 MarkWest senior notes, 4.500% - 5.500%, due 2023 - 2025 63 63 Capital lease obligations due 2016-2028 319 348 Total 11,069 12,475 Unamortized debt issuance costs (44 ) (51 ) Unamortized discount (a) (453 ) (499 ) Amounts due within one year (28 ) (29 ) Total long-term debt due after one year $ 10,544 $ 11,896 (a) Includes $420 million and $464 million discount as of December 31, 2016 and December 31, 2015 , respectively, related to the difference at the time of the acquisition between the fair value and the principal amount of the assumed MarkWest debt. The following table shows five years of scheduled debt payments. (In millions) 2017 $ 28 2018 630 2019 477 2020 683 2021 1,031 Commercial Paper On February 26, 2016, we established a commercial paper program that allows us to have a maximum of $2 billion in commercial paper outstanding, with maturities up to 397 days from the date of issuance. We do not intend to have outstanding commercial paper borrowings in excess of available capacity under our bank revolving credit facilities. During 2016 , we borrowed and repaid $1.26 billion under the commercial paper program. At December 31, 2016 , we had no amounts outstanding under the commercial paper program. MPC Bank Revolving Credit Facilities On July 20, 2016, we entered into a credit agreement with a syndicate of lenders to replace our existing MPC bank revolving credit facility due in 2017. The new agreement provides for a four -year $2.5 billion bank revolving credit facility (our “four-year revolving credit facility”) maturing on July 20, 2020 . Additionally, we entered into a 364 -day $1 billion bank revolving credit facility (our “364-day revolving credit facility” and together with our four-year revolving credit facility, our “revolving credit facilities”) maturing on July 19, 2017 . Our four-year revolving credit facility includes letter of credit issuing capacity of up to $2.0 billion and swingline loan capacity of up to $100 million . We may increase our borrowing capacity under our four-year revolving credit facility by up to an additional $500 million , subject to certain conditions including the consent of the lenders whose commitments would be increased. In addition, the maturity date of the four-year revolving credit facility may be extended for up to two additional one -year periods subject to the approval of lenders holding a majority of the commitments then outstanding, provided that the commitments of any non-consenting lenders will terminate on the then-effective maturity date. Borrowings under our revolving credit facilities bear interest, at our election, at either the Adjusted LIBO Rate (as defined in our revolving credit facilities) plus a margin or the Alternate Base Rate (as defined in our revolving credit facilities), plus a margin . We are charged various fees and expenses under our revolving credit facilities, including administrative agent fees, commitment fees on the unused portion of our borrowing capacity and fees related to issued and outstanding letters of credit. The applicable margin to the benchmark interest rates and the margin to the benchmark commitment fees payable under our revolving credit facilities fluctuate from time-to-time based on our credit ratings. Our revolving credit facilities contain certain representations and warranties, affirmative and restrictive covenants and events of default that we consider to be usual and customary for arrangements of this type, including a financial covenant that requires us to maintain a ratio of Consolidated Net Debt to Total Capitalization (each as defined in our revolving credit facility) of no greater than 0.65 to 1.00 as of the last day of each fiscal quarter. Other covenants, among other things, restrict our ability to incur debt, create liens on our assets or enter into transactions with affiliates. As of December 31, 2016 , we were in compliance with the covenants contained in the revolving credit facilities. There were no borrowings or letters of credit outstanding at December 31, 2016 . Trade Receivables Securitization Facility On July 20, 2016, we amended our trade receivables securitization facility (“trade receivables facility”) to, among other things, reduce the capacity from $1 billion to $750 million and to extend the maturity date to July 19, 2019 . The reduction in capacity reflects the lower refined product price environment. The trade receivables facility consists of one of our wholly-owned subsidiaries, Marathon Petroleum Company LP (“MPC LP”), selling or contributing on an on-going basis all of its trade receivables (including trade receivables acquired from Marathon Petroleum Trading Canada LLC, a wholly-owned subsidiary of MPC LP), together with all related security and interests in the proceeds thereof, without recourse, to another wholly-owned, bankruptcy-remote special purpose subsidiary, MPC Trade Receivables Company LLC (“TRC”), in exchange for a combination of cash, equity and/or a subordinated note issued by TRC to MPC LP. TRC, in turn, has the ability to finance its purchase of the receivables from MPC LP by selling undivided ownership interests in qualifying trade receivables, together with all related security and interests in the proceeds thereof, without recourse, to the purchasing group in exchange for cash proceeds. The trade receivables facility also provides for the issuance of letters of credit up to $750 million , provided that the aggregate credit exposure of the purchasing group, including outstanding letters of credit, may not exceed the lesser of $750 million or the balance of our eligible trade receivables at any one time. To the extent that TRC retains an ownership interest in the receivables it has purchased or received from MPC LP, such interest will be included in our consolidated financial statements solely as a result of the consolidation of the financial statements of TRC with those of MPC. The receivables sold or contributed to TRC are available first and foremost to satisfy claims of the creditors of TRC and are not available to satisfy the claims of creditors of MPC. TRC has granted a security interest in all of its assets to the purchasing group to secure its obligations under the Receivables Purchase Agreement. Proceeds from the sale of undivided percentage ownership interests in qualifying receivables under the trade receivables facility will be reflected as debt on our consolidated balance sheet. We will remain responsible for servicing the receivables sold to the purchasing group. TRC pays floating-rate interest charges and usage fees on amounts outstanding under the trade receivables facility, if any, and certain other fees related to the administration of the facility and letters of credit that are issued and outstanding under the trade receivables facility. The Receivables Purchase Agreement and Second Amended and Restated Receivables Sale Agreement include representations and covenants that we consider usual and customary for arrangements of this type. Trade receivables are subject to customary criteria, limits and reserves before being deemed to qualify for sale by TRC pursuant to the trade receivables facility. In addition, further purchases of qualified trade receivables under the trade receivables facility are subject to termination, and TRC may be subject to default fees, upon the occurrence of certain amortization events that are included in the Receivables Purchase Agreement, all of which we consider to be usual and customary for arrangements of this type. At December 31, 2016 , we were in compliance with the covenants contained in the Receivables Purchase Agreement and Second Amended and Restated Receivables Sale Agreement. During 2016 , we borrowed $430 million under the trade receivables securitization facility at an average interest rate of 1.4 percent and repaid all of these borrowings. There were no borrowings or letters of credit outstanding under the trade receivables facility at December 31, 2016 . As of December 31, 2016 , eligible trade receivables supported borrowings and letter of credit issuances of $684 million . MPC Term Loan Agreement On August 26, 2014 , we entered into a $700 million five -year senior unsecured term loan credit agreement (“term loan agreement”) with a syndicate of lenders to fund a portion of the purchase price for the acquisition of Hess’ Retail Operations and Related Assets. The term loan was drawn in full on September 24, 2014. The term loan agreement matures on September 24, 2019 and may be prepaid at any time without premium or penalty. We pay certain customary fees under the term loan agreement, including an annual administrative fee to the administrative agent. On September 30, 2016, we prepaid $500 million under the MPC term loan agreement with available cash on hand. As of December 31, 2016 , $200 million in borrowings was outstanding under the term loan agreement. Borrowings under the term loan agreement bear interest, at our election, at either the Adjusted LIBO Rate (as defined in the term loan agreement) plus a margin or the Alternate Base Rate (as defined in the term loan agreement) plus a margin . The applicable margin to the benchmark interest rates fluctuate from time-to-time based on our credit ratings. The borrowings under this facility during 2016 were at an average interest rate of 1.6 percent . The term loan agreement contains representation and warranties, affirmative and negative covenants and events of default that are substantially similar to those contained in our revolving credit facilities, which we consider to be usual and customary for an agreement of this type. Among other things, our term loan agreement requires us to maintain, as of the last day of each fiscal quarter, a ratio of Consolidated Net Debt to Total Capitalization (as defined in the term loan agreement) of no greater than 0.65 to 1.00. As of December 31, 2016 , we were in compliance with the covenants contained in the term loan agreement. MPC Senior Notes On December 14, 2015, we completed a public offering of $1.5 billion in aggregate principal amount of unsecured senior notes (the “new MPC senior notes”), consisting of $600 million aggregate principal amount of 2.700% senior notes due 2018, $650 million aggregate principal amount of 3.400% senior notes due 2020 and $250 million aggregate principal amount of 5.850% senior notes due 2045. The net proceeds from the offering of the new MPC senior notes were $1.49 billion , after deducting underwriting discounts and offering expenses. We used a majority of the net proceeds from this offering to extinguish the $750 million aggregate principal amount of our 3.500% senior notes due 2016. During December 2015, we deposited $763 million with our senior notes trustee in full satisfaction of our obligations for the 3.500% senior notes due 2016. Under the terms of the senior notes indenture governing the 3.500% senior notes due 2016, our obligations related to these notes, including the payment of principal and interest to the maturity date, was discharged in full upon making such deposit. As a result, we recorded a loss on extinguishment of debt of $5 million . We used the remaining net proceeds from the new MPC senior notes for general corporate purposes. Interest on each series of the new MPC senior notes is payable semi-annually in arrears on June 15 and December 15, commencing on June 15, 2016. The new MPC senior notes are unsecured and unsubordinated obligations of MPC and rank equally with its other existing and future unsecured and unsubordinated indebtedness. The new MPC senior notes are structurally subordinate to the secured and unsecured debt of MPC’s subsidiaries, including all debt of MPLX and its subsidiaries. MPLX Credit Agreement MPLX is party to a credit agreement, dated as of November 20, 2014, and amended as of October 27, 2015 (“MPLX credit agreement”), providing for a $2 billion bank revolving credit facility with a maturity date of December 4, 2020 and an outstanding $250 million term loan facility with a maturity date of November 20, 2019 . The MPLX credit agreement includes letter of credit issuing capacity of up to $250 million and swingline loan capacity of up to $100 million . The revolving borrowing capacity under the MPLX credit agreement may be increased by up to an additional $500 million , subject to certain conditions, including the consent of the lenders whose commitments would increase. In addition, the maturity date of the bank revolving credit facility may be extended from time-to-time during its term to a date that is one year after the then-effective maturity date, subject to the approval of lenders holding the majority of the loans and commitments then outstanding, provided that the commitments of any non-consenting lenders will be terminated on the then-effective maturity date. The maturity date for the term loan facility may be extended for up to two additional one -year periods subject to the consent of the lenders holding a majority of the outstanding term loan borrowings, provided that the portion of the term loan borrowings held by any non-consenting lenders will continue to be due and payable on the then-effective maturity date. Borrowings under the MPLX credit agreement bear interest, at our election, at the Adjusted LIBO Rate or the Alternate Base Rate (as defined in the MPLX credit agreement) plus a specified margin. MPLX is charged various fees and expenses in connection with the agreement, including administrative agent fees, commitment fees on the unused portion of the borrowing capacity and fees with respect to issued and outstanding letters of credit. The applicable margins to the benchmark interest rates and the commitment fees payable under the MPLX credit agreement fluctuate from time-to-time based on MPLX’s credit ratings. The MPLX credit agreement includes certain representations and warranties, affirmative and restrictive covenants and events of default that we consider to be usual and customary for an agreement of this type, including a financial covenant that requires MPLX to maintain a ratio of Consolidated Total Debt as of the end of each fiscal quarter to Consolidated EBITDA (both as defined in the MPLX credit agreement) for the prior four fiscal quarters of no greater than 5.0 to 1.0 (or 5.5 to 1.0 for up to two fiscal quarters following certain acquisitions). Consolidated EBITDA is subject to adjustments for certain acquisitions completed and capital projects undertaken during the relevant period. Other covenants, among other things, restrict MPLX and certain of its subsidiaries from incurring debt, creating liens on its assets and entering into transactions with affiliates. As of December 31, 2016 , MPLX was in compliance with the covenants contained in the MPLX credit agreement. In connection with the closing of the MarkWest Merger, MarkWest’s existing credit facility was terminated and the approximately $943 million outstanding under MarkWest’s bank revolving credit facility was repaid with $850 million of borrowings under MPLX’s bank revolving credit facility and $93 million in cash. During 2016 , MPLX borrowed $434 million under the bank revolving credit facility, at an average interest rate of 1.9 percent , per annum, and repaid $1.31 billion of these borrowings. At December 31, 2016 , MPLX had no outstanding borrowings and $3 million of letters of credit outstanding under the bank revolving credit facility, resulting in total unused loan availability of $2 billion . At December 31, 2016 , MPLX had $250 million in borrowings outstanding under the term loan facility that bore interest at an average rate of 2.0 percent during 2016 . MPLX and MarkWest Senior Notes In connection with the MarkWest Merger, MPLX assumed MarkWest’s outstanding debt, which included $4.1 billion aggregate principal amount of senior notes outstanding. On December 22, 2015, approximately $4.04 billion aggregate principal amount of MarkWest’s outstanding senior notes were exchanged for an aggregate principal amount of approximately $4.04 billion of new unsecured senior notes issued by MPLX and cash of $1 for each $1,000 of principal amount exchanged in an exchange offer and consent solicitation undertaken by MPLX and MarkWest. The new MPLX senior notes consist of approximately $710 million aggregate principal amount of 5.500% senior notes due February 15, 2023, approximately $989 million aggregate principal amount of 4.500% senior notes due July 15, 2023, approximately $1.15 billion aggregate principal amount of 4.875% senior notes due December 1, 2024 and approximately $1.19 billion aggregate principal amount of 4.875% senior notes due June 1, 2025. Interest on each series of new MPLX senior notes is payable semi-annually in arrears on February 15 th and August 15 th of each year with respect to the 5.500% 2023 senior notes, on January 15 th and July 15 th of each year with respect to the 4.500% 2023 senior notes and on June 1 st and December 1 st of each year with respect to the 4.875% 2024 senior notes and the 4.875% 2025 senior notes. After giving effect to the exchange offer and consent solicitation referred to above, as of December 31, 2016, MarkWest had outstanding approximately $40 million aggregate principal amount of 5.500% senior notes due February 15, 2023, approximately $11 million aggregate principal amount of 4.500% senior notes due July 15, 2023, approximately $1 million aggregate principal amount of 4.875% senior notes due December 1, 2024 and approximately $11 million aggregate principal amount of 4.875% senior notes due June 1, 2025. Interest on each series of the MarkWest senior notes is payable semi-annually in arrears on February 15 th and August 15 th of each year with respect to the 5.500% 2023 senior notes, on January 15 th and July 15 th of each year with respect to the 4.500% 2023 senior notes and on June 1 st and December 1 st of each year with respect to the 4.875% 2024 senior notes and the 4.875% 2025 senior notes. The new MPLX notes are unsecured senior obligations of MPLX and rank equally in right of payment with all of its other senior unsecured debt and are structurally subordinate to the secured and unsecured debt of MPLX’s subsidiaries, including any debt of MarkWest that remains outstanding. On February 12, 2015, MPLX completed a public offering of $500 million aggregate principal amount of four percent unsecured senior notes due February 15, 2025 . The net proceeds, which were approximately $495 million after deducting underwriting discounts, were used to repay the amounts outstanding under the MPLX bank revolving credit facility, as well as for general partnership purposes. Interest is payable semi-annually in arrears on February 15 th and August 15 th of each year.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2016
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information (In millions) 2016 2015 2014 Net cash provided by operating activities included: Interest paid (net of amounts capitalized) $ 478 $ 272 $ 166 Net income taxes paid to taxing authorities 140 1,605 1,362 Non-cash investing and financing activities: Capital lease obligations increase $ — $ 1 $ — Contribution of assets to joint venture (a) 272 — — Property, plant and equipment sold — 5 4 Property, plant and equipment acquired — 5 4 Acquisition: Fair value of MPLX units issued (b) — 7,326 — Payable to MPLX Class B unitholders — 50 — (a) Speedway’s contribution of travel plaza locations to new joint venture with Pilot Flying J. (b) See Note 5 . 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: (In millions) 2016 2015 2014 Additions to property, plant and equipment per consolidated statements of cash flows $ 2,892 $ 1,998 $ 1,480 Non-cash additions to property, plant and equipment — 5 4 Asset retirement expenditures (a) 6 1 2 Increase (decrease) in capital accruals (127 ) 94 95 Total capital expenditures before acquisitions 2,771 2,098 1,581 Acquisitions (b) (133 ) 11,397 2,744 Total capital expenditures $ 2,638 $ 13,495 $ 4,325 (a) Included in All other, net – Operating activities on the consolidated statements of cash flows. (b) 2016 includes adjustments to the fair values of property, plant and equipment, intangibles and goodwill acquired in connection with the MarkWest Merger. The 2015 acquisitions include the MarkWest Merger. The 2014 acquisitions include the acquisition of Hess’ Retail Operations and Related Assets. The acquisition numbers above include property, plant and equipment, intangibles and goodwill. See Note 5 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2016
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, 2014 $ (217 ) $ (104 ) $ 4 $ 4 $ (313 ) Other comprehensive income (loss) before reclassifications (44 ) 31 — (1 ) (14 ) Amounts reclassified from accumulated other comprehensive loss: Amortization – prior service credit (a) (46 ) (4 ) — — (50 ) – actuarial loss (a) 51 8 — — 59 – settlement loss (a) 4 — — — 4 Tax effect (3 ) (1 ) — — (4 ) Other comprehensive income (loss) (38 ) 34 — (1 ) (5 ) Balance as of December 31, 2015 $ (255 ) $ (70 ) $ 4 $ 3 $ (318 ) (In millions) Pension Benefits Other Benefits Gain on Cash Flow Hedge Workers Compensation Total Balance as of December 31, 2015 $ (255 ) $ (70 ) $ 4 $ 3 $ (318 ) Other comprehensive income before reclassifications 22 64 — — 86 Amounts reclassified from accumulated other comprehensive loss: Amortization – prior service credit (a) (46 ) (3 ) — — (49 ) – actuarial loss (a) 38 2 — — 40 – settlement loss (a) 7 — — — 7 Other (b) — — — (1 ) (1 ) Tax effect 1 — — — 1 Other comprehensive income (loss) 22 63 — (1 ) 84 Balance as of December 31, 2016 $ (233 ) $ (7 ) $ 4 $ 2 $ (234 ) (a) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 22 . (b) This amount was reclassified out of accumulated other comprehensive loss and is included in selling, general and administrative on the consolidated statements of income.

Defined Benefit Pension and Oth

Defined Benefit Pension and Other Postretirement Plans	12 Months Ended
	Dec. 31, 2016
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Defined Benefit Pension and Other Postretirement Plans	Defined Benefit Pension and Other Postretirement Plans We have noncontributory defined benefit pension plans covering substantially all employees. Benefits under these plans have been based primarily on age, years of service and final average pensionable earnings. The years of service component of this formula was frozen as of December 31, 2009. Benefits for service beginning January 1, 2010 are based on a cash balance formula with an annual percentage of eligible pay credited based upon age and years of service. Eligible Speedway employees accrue benefits under a defined contribution plan for service years beginning January 1, 2010. We also have other postretirement benefits covering most employees. Health care benefits are provided through comprehensive hospital, surgical and major medical benefit provisions subject to various cost-sharing features. Retiree life insurance benefits are provided to a closed group of retirees. Other postretirement benefits are not funded in advance. Obligations and funded status – The accumulated benefit obligation for all defined benefit pension plans was $1,914 million and $1,918 million as of December 31, 2016 and 2015 . The following summarizes our defined benefit pension plans that have accumulated benefit obligations in excess of plan assets. December 31, (In millions) 2016 2015 Projected benefit obligations $ 2,024 $ 1,997 Accumulated benefit obligations 1,914 1,918 Fair value of plan assets 1,659 1,570 The following summarizes the projected benefit obligations and funded status for our defined benefit pension and other postretirement plans: Pension Benefits Other Benefits (In millions) 2016 2015 2016 2015 Change in benefit obligations: Benefit obligations at January 1 $ 1,997 $ 2,075 $ 800 $ 812 Service cost 114 101 32 31 Interest cost 73 71 35 32 Actuarial (gain) loss 15 (63 ) (101 ) (63 ) Benefits paid (175 ) (187 ) (26 ) (24 ) Other (a) — — — 12 Benefit obligations at December 31 2,024 1,997 740 800 Change in plan assets: Fair value of plan assets at January 1 1,570 1,744 — — Actual return on plan assets 145 (33 ) — — Employer contributions 119 46 26 24 Benefits paid from plan assets (175 ) (187 ) (26 ) (24 ) Fair value of plan assets at December 31 1,659 1,570 — — Funded status of plans at December 31 $ (365 ) $ (427 ) $ (740 ) $ (800 ) Amounts recognized in the consolidated balance sheets: Current liabilities $ (18 ) $ (19 ) $ (32 ) $ (29 ) Noncurrent liabilities (347 ) (408 ) (708 ) (771 ) Accrued benefit cost $ (365 ) $ (427 ) $ (740 ) $ (800 ) Pretax amounts recognized in accumulated other comprehensive loss: (b) Net actuarial loss $ 645 $ 723 $ 17 $ 120 Prior service credit (276 ) (323 ) (6 ) (9 ) (a) Includes adjustments related to the MarkWest Merger in 2015. (b) Amounts exclude those related to LOOP and Explorer, equity method investees with defined benefit pension and postretirement plans for which net losses of $16 million and less than $1 million were recorded in accumulated other comprehensive loss in 2016 , reflecting our ownership share. Components of net periodic benefit cost and other comprehensive loss – The following summarizes the net periodic benefit costs and the amounts recognized as other comprehensive loss for our defined benefit pension and other postretirement plans. Pension Benefits Other Benefits (In millions) 2016 2015 2014 2016 2015 2014 Components of net periodic benefit cost: Service cost $ 114 $ 101 $ 88 $ 32 $ 31 $ 27 Interest cost 73 71 74 35 32 33 Expected return on plan assets (98 ) (98 ) (107 ) — — — Amortization – prior service credit (46 ) (46 ) (46 ) (3 ) (4 ) (4 ) – actuarial loss 38 51 51 2 8 2 – settlement loss 7 4 96 — — — Net periodic benefit cost (a) $ 88 $ 83 $ 156 $ 66 $ 67 $ 58 Other changes in plan assets and benefit obligations recognized in other comprehensive loss (pretax): Actuarial (gain) loss $ (33 ) $ 69 $ 188 $ (101 ) $ (63 ) $ 86 Prior service cost (b) — — — — 13 — Amortization of actuarial loss (45 ) (55 ) (147 ) (2 ) (8 ) (2 ) Amortization of prior service cost 46 46 46 3 4 4 Other — — — — — — Total recognized in other comprehensive loss $ (32 ) $ 60 $ 87 $ (100 ) $ (54 ) $ 88 Total recognized in net periodic benefit cost and other comprehensive loss $ 56 $ 143 $ 243 $ (34 ) $ 13 $ 146 (a) Net periodic benefit cost reflects a calculated market-related value of plan assets which recognizes changes in fair value over three years. (b) Includes adjustments related to the MarkWest Merger in 2015. Lump sum payments to employees retiring in 2016 , 2015 and 2014 exceeded the plan’s total service and interest costs expected for those years. Settlement losses are required to be recorded when lump sum payments exceed total service and interest costs. As a result, pension settlement expenses were recorded in 2016 , 2015 and 2014 related to our cumulative lump sum payments made during those years. The estimated net actuarial loss and prior service credit for our defined benefit pension plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost in 2017 are $35 million and $39 million , respectively. The estimated net actuarial loss and prior service credit for our other defined benefit postretirement plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost in 2017 is $2 million and $3 million , respectively. Plan assumptions – The following summarizes the assumptions used to determine the benefit obligations at December 31, and net periodic benefit cost for the defined benefit pension and other postretirement plans for 2016 , 2015 and 2014 . Pension Benefits Other Benefits 2016 2015 2014 2016 2015 2014 Weighted-average assumptions used to determine benefit obligation: Discount rate 3.90 % 4.00 % 3.65 % 4.25 % 4.50 % 4.15 % Rate of compensation increase 5.00 % 3.70 % 3.70 % 5.00 % 3.70 % 3.70 % Weighted-average assumptions used to determine net periodic benefit cost: Discount rate 3.80 % 3.70 % 4.05 % 4.50 % 4.30 % 4.95 % Expected long-term return on plan assets (a) 6.50 % 6.75 % 7.00 % — % — % — % Rate of compensation increase 5.00 % 3.70 % 3.70 % 5.00 % 3.70 % 3.70 % (a) Effective January 1, 2017, the expected long-term rate of return on plan assets is 6.50 percent due to a continuation of a change in our primary plan investment strategy, which began January 1, 2014. Expected long-term return on plan assets The overall expected long-term return on plan assets assumption is determined based on an asset rate-of-return modeling tool developed by a third-party investment group. The tool utilizes underlying assumptions based on actual returns by asset category and inflation and takes into account our asset allocation to derive an expected long-term rate of return on those assets. Capital market assumptions reflect the long-term capital market outlook. The assumptions for equity and fixed income investments are developed using a building-block approach, reflecting observable inflation information and interest rate information available in the fixed income markets. Long-term assumptions for other asset categories are based on historical results, current market characteristics and the professional judgment of our internal and external investment teams. Assumed health care cost trend The following summarizes the assumed health care cost trend rates. December 31, 2016 2015 2014 Health care cost trend rate assumed for the following year: Medical: Pre-65 7.00 % 7.50 % 8.00 % Prescription drugs 9.00 % 7.00 % 7.00 % Rate to which the cost trend rate is assumed to decline (the ultimate trend rate): Medical: Pre-65 4.50 % 5.00 % 5.00 % Prescription drugs 4.50 % 5.00 % 5.00 % Year that the rate reaches the ultimate trend rate: Medical: Pre-65 2026 2021 2021 Prescription drugs 2026 2021 2021 Increases in the post-65 medical plan premium for the Marathon Petroleum Health Plan and the Marathon Petroleum Retiree Health Plan are the lower of the trend rate or four percent . Assumed health care cost trend rates have a significant effect on the amounts reported for defined benefit retiree health care plans. A one percentage point change in assumed health care cost trend rates would have the following effects: 1-Percentage- 1-Percentage- (In millions) Point Increase Point Decrease Effect on total of service and interest cost components $ 6 $ (5 ) Effect on other postretirement benefit obligations 33 (29 ) Plan investment policies and strategies The investment policies for our pension plan assets reflect the funded status of the plans and expectations regarding our future ability to make further contributions. Long-term investment goals are to: (1) manage the assets in accordance with the legal requirements of all applicable laws; (2) diversify plan investments across asset classes to achieve an optimal balance between risk and return and between income and growth of assets through capital appreciation; and (3) source benefit payments primarily through existing plan assets and anticipated future returns. The investment goals are implemented to manage the plans’ funded status volatility and minimize future cash contributions. The asset allocation strategy will change over time in response to changes primarily in funded status, which is dictated by current and anticipated market conditions, the independent actions of our investment committee, required cash flows to and from the plans and other factors deemed appropriate. Such changes in asset allocation are intended to allocate additional assets to the fixed income asset class should the funded status improve. The fixed income asset class shall be invested in such a manner that its interest rate sensitivity correlates highly with that of the plans’ liabilities. Other asset classes are intended to provide additional return with associated higher levels of risk. Investment performance and risk is measured and monitored on an ongoing basis through quarterly investment meetings and periodic asset and liability studies. At December 31, 2016 , the primary plan’s targeted asset allocation was 51 percent equity, private equity, real estate, and timber securities and 49 percent fixed income securities. Fair value measurements Plan assets are measured at fair value. The following provides a description of the valuation techniques employed for each major plan asset category at December 31, 2016 and 2015 . Cash and cash equivalents – Cash and cash equivalents include a collective fund serving as the investment vehicle for the cash reserves and cash held by third-party investment managers. The collective fund is valued at net asset value (“NAV”) on a scheduled basis using a cost approach, and is considered a Level 2 asset. Cash and cash equivalents held by third-party investment managers are valued using a cost approach and are considered Level 2. Equity – Equity investments includes common stock, mutual and pooled funds. Common stock investments are valued using a market approach, which are priced daily in active markets and are considered Level 1. Mutual and pooled equity funds are well diversified portfolios, representing a mix of strategies in domestic, international and emerging market strategies. Mutual funds are publicly registered, valued at NAV on a daily basis using a market approach and are considered Level 1 assets. Pooled funds are valued at NAV using a market approach and are considered Level 2. Fixed Income – Fixed income investments include corporate bonds, U.S. dollar treasury bonds and municipal bonds. These securities are priced on observable inputs using a combination of market, income and cost approaches. These securities are considered Level 2 assets. Fixed income also includes a well diversified bond portfolio structured as a pooled fund. This fund is valued at NAV on a daily basis using a market approach and is considered Level 2. Private Equity – Private equity investments include interests in limited partnerships which are valued using information provided by external managers for each individual investment held in the fund. These holdings are considered Level 3. Real Estate – Real estate investments consist of interests in limited partnerships. These holdings are either appraised or valued using investment manager’s assessment of assets held. These holdings are considered Level 3. Other – Other investments include two limited liability companies (“LLCs”) with no public market. The LLCs were formed to acquire timberland in the northwest U.S. These holdings are either appraised or valued using investment manager’s assessment of assets held. These holdings are considered Level 3. Other investments classified as Level 1 include publicly traded depository receipts. The following tables present the fair values of our defined benefit pension plans’ assets, by level within the fair value hierarchy, as of December 31, 2016 and 2015 . December 31, 2016 (In millions) Level 1 Level 2 Level 3 Total Cash and cash equivalents $ — $ 24 $ — $ 24 Equity: Common stocks 71 — — 71 Mutual funds 160 — — 160 Pooled funds — 451 — 451 Fixed income: Corporate — 570 — 570 Government — 90 — 90 Pooled funds — 173 — 173 Private equity — — 60 60 Real estate — — 39 39 Other 2 — 19 21 Total investments, at fair value $ 233 $ 1,308 $ 118 $ 1,659 December 31, 2015 (In millions) Level 1 Level 2 Level 3 Total Cash and cash equivalents $ — $ 27 $ — $ 27 Equity: Common stocks 57 — — 57 Mutual funds 142 — — 142 Pooled funds — 399 — 399 Fixed income: Corporate — 516 — 516 Government — 103 — 103 Pooled funds — 193 — 193 Private equity — — 62 62 Real estate — — 50 50 Other 2 — 19 21 Total investments, at fair value $ 201 $ 1,238 $ 131 $ 1,570 The following is a reconciliation of the beginning and ending balances recorded for plan assets classified as Level 3 in the fair value hierarchy: 2016 (In millions) Private Equity Real Estate Other Total Beginning balance $ 62 $ 50 $ 19 $ 131 Actual return on plan assets: Realized 8 5 — 13 Unrealized 2 (3 ) — (1 ) Purchases 2 1 — 3 Sales (14 ) (14 ) — (28 ) Ending balance $ 60 $ 39 $ 19 $ 118 2015 (In millions) Private Equity Real Estate Other Total Beginning balance $ 66 $ 57 $ 21 $ 144 Actual return on plan assets: Realized 12 6 — 18 Unrealized (1 ) (3 ) (2 ) (6 ) Purchases 5 5 — 10 Sales (20 ) (15 ) — (35 ) Ending balance $ 62 $ 50 $ 19 $ 131 Cash Flows Contributions to defined benefit plans – Our funding policy with respect to the funded pension plans is to contribute amounts necessary to satisfy minimum pension funding requirements, including requirements of the Pension Protection Act of 2006, plus such additional, discretionary, amounts from time to time as determined appropriate by management. In 2016 , we made pension contributions totaling $119 million . We have no required funding for 2017 , but may make voluntary contributions at our discretion. Cash contributions to be paid from our general assets for the unfunded pension and postretirement plans are estimated to be approximately $14 million and $32 million , respectively, in 2017 . Estimated future benefit payments – The following gross benefit payments, which reflect expected future service, as appropriate, are expected to be paid in the years indicated. (In millions) Pension Benefits Other Benefits 2017 $ 174 $ 32 2018 177 35 2019 182 37 2020 165 39 2021 165 41 2022 through 2026 801 222 Contributions to defined contribution plans – We also contribute to several defined contribution plans for eligible employees. Contributions to these plans totaled $113 million , $94 million and $86 million in 2016 , 2015 and 2014 , respectively. Multiemployer Pension Plan We contribute to one multiemployer defined benefit pension plan under the terms of a collective-bargaining agreement that covers some of our union-represented employees. The risks of participating in this multiemployer plan are different from single-employer plans in the following aspects: • Assets contributed to the multiemployer plan by one employer may be used to provide benefits to employees of other participating employers. • If a participating employer stops contributing to the plan, the unfunded obligations of the plan may be borne by the remaining participating employers. • If we choose to stop participating in the multiemployer plan, we may be required to pay that plan an amount based on the underfunded status of the plan, referred to as a withdrawal liability. Our participation in this plan for 2016 , 2015 and 2014 is outlined in the table below. The “EIN” column provides the Employee Identification Number for the plan. The most recent Pension Protection Act zone status available in 2016 and 2015 is for the plan’s year ended December 31, 2015 and December 31, 2014, respectively. The zone status is based on information that we received from the plan and is certified by the plan’s actuary. Among other factors, plans in the red zone are generally less than 65 percent funded. The “FIP/RP Status Pending/Implemented” column indicates a financial improvement plan or a rehabilitation plan has been implemented. The last column lists the expiration date of the collective-bargaining agreement to which the plan is subject. There have been no significant changes that affect the comparability of 2016 , 2015 and 2014 contributions. Our portion of the contributions does not make up more than five percent of total contributions to the plan. Pension Protection Act Zone Status FIP/RP Status Pending/Implemented MPC Contributions In millions ) Surcharge Expiration Date of Collective – Bargaining Pension Fund EIN 2016 2015 2016 2015 2014 Central States, Southeast and Southwest Areas Pension Plan (a) 36-6044243 Red Red Implemented $ 4 $ 4 $ 4 No January 31, 2019 (a) This agreement has a minimum contribution requirement of $303 per week per employee for 2017 . A total of 280 employees participated in the plan as of December 31, 2016 . Multiemployer Health and Welfare Plan We contribute to one multiemployer health and welfare plan that covers both active employees and retirees. Through the health and welfare plan employees receive medical, dental, vision, prescription and disability coverage. Our contributions to this plan totaled $6 million , $7 million and $6 million for 2016 , 2015 and 2014 , respectively.

Stock-Based Compensation Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Plans	Stock-Based Compensation Plans Description of the Plans Effective April 26, 2012, our employees and non-employee directors became eligible to receive equity awards under the Marathon Petroleum Corporation 2012 Incentive Compensation Plan (“MPC 2012 Plan”). The MPC 2012 Plan authorizes the Compensation Committee of our board of directors (“Committee”) to grant non-qualified or incentive stock options, stock appreciation rights, stock awards (including restricted stock and restricted stock unit awards), cash awards and performance awards to our employees and non-employee directors. Under the MPC 2012 Plan, no more than 50 million shares of our common stock may be delivered and no more than 20 million shares of our common stock may be the subject of awards that are not stock options or stock appreciation rights. In the sole discretion of the Committee, 20 million shares of our common stock may be granted as incentive stock options. Shares issued as a result of awards granted under these plans are funded through the issuance of new MPC common shares. Prior to April 26, 2012, our employees and non-employee directors were eligible to receive equity awards under the Marathon Petroleum Corporation 2011 Second Amended and Restated Incentive Compensation Plan (“MPC 2011 Plan”). Stock-based awards under the Plans We expense all share-based payments to employees and non-employee directors based on the grant date fair value of the awards over the requisite service period, adjusted for estimated forfeitures. Stock Options – We grant stock options to certain officer and non-officer employees. All of the stock options granted in 2016 fell under the MPC 2012 Plan. Stock options awarded under the MPC 2011 Plan and the MPC 2012 Plan represent the right to purchase shares of our common stock at its fair market value, which is the closing price of MPC’s common stock on the date of grant. Stock options have a maximum term of ten years from the date they are granted, and vest over a requisite service period of three years . We use the Black Scholes option-pricing model to estimate the fair value of stock options granted, which requires the input of subjective assumptions. Restricted Stock and Restricted Stock Units – We grant restricted stock and restricted stock units to employees and non-employee directors. In general, restricted stock and restricted stock units granted to employees vest over a requisite service period of three years . Restricted stock and restricted stock unit awards granted after 2011 to officers are subject to an additional one year holding period after the three-year vesting period. Restricted stock recipients who received grants in 2012 and after have the right to vote such stock; however, dividends are accrued and will be paid upon vesting. Restricted stock units granted to non-employee directors are considered to vest immediately at the time of the grant for accounting purposes, as they are non-forfeitable, but are not issued until the director’s departure from the board of directors. Restricted stock unit recipients do not have the right to vote such shares and receive dividend equivalents payable upon vesting. The non-vested shares are not transferable and are held by our transfer agent. The fair values of restricted stock are equal to the market price of our common stock on the grant date. Performance Units – We grant performance unit awards to certain officer employees. Performance units are dollar denominated. The target value of all performance units is $1.00 , with actual payout up to $2.00 per unit (up to 200 percent of target). Performance units issued under the MPC 2012 Plan have a 36 -month requisite service period. The payout value of these awards will be determined by the relative ranking of the total shareholder return (“TSR” ) of MPC common stock compared to the TSR of a select group of peer companies, as well as the Standard & Poor’s 500 Energy Index fund over an average of four measurement periods. These awards will be settled 25 percent in MPC common stock and 75 percent in cash. The number of shares actually distributed will be determined by dividing 25 percent of the final payout by the closing price of MPC common stock on the day the Committee certifies the final TSR rankings, or the next trading day if the certification is made outside of normal trading hours. The performance units paying out in cash are accounted for as liability awards and recorded at fair value with a mark-to-market adjustment made each quarter. The performance units that settle in shares are accounted for as equity awards. Total Stock-Based Compensation Expense The following table reflects activity related to our stock-based compensation arrangements: (In millions) 2016 2015 2014 Stock-based compensation expense $ 45 $ 42 $ 40 Tax benefit recognized on stock-based compensation expense 17 16 15 Cash received by MPC upon exercise of stock option awards 10 33 26 Tax benefit received for tax deductions for stock awards exercised 4 26 19 Stock Option Awards The Black Scholes option-pricing model values used to value stock option awards granted were determined based on the following weighted average assumptions: 2016 2015 2014 Weighted average exercise price per share $ 35.27 $ 50.85 $ 42.51 Expected life in years 6.2 6.0 5.8 Expected volatility 38 % 33 % 36 % Expected dividend yield 3.0 % 2.0 % 1.9 % Risk-free interest rate 1.4 % 1.7 % 1.8 % Weighted average grant date fair value of stock option awards granted $ 9.84 $ 13.44 $ 12.69 The expected life of stock options granted is based on historical data and represents the period of time that options granted are expected to be held prior to exercise. The 2016 assumption for expected volatility of our stock price reflects a weighting of 50 percent of our common stock implied volatility and 50 percent of our common stock historical volatility. The risk-free interest rate for periods within the expected life of the option is based on the U.S. Treasury yield curve in effect at the time of the grant. The following is a summary of our common stock option activity in 2016 : Number of of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Terms (in years) Aggregate Intrinsic Value (in millions) Outstanding at December 31, 2015 8,724,631 $ 27.16 Granted 1,474,177 35.27 Exercised (637,761 ) 18.78 Forfeited, canceled or expired (29,607 ) 42.91 Outstanding at December 31, 2016 9,531,440 28.93 Vested and expected to vest at December 31, 2016 9,518,269 28.90 5.4 $ 205 Exercisable at December 31, 2016 7,094,204 24.90 4.3 181 The intrinsic value of options exercised by MPC employees during 2016 , 2015 and 2014 was $14 million , $60 million and $48 million , respectively. As of December 31, 2016 , unrecognized compensation cost related to stock option awards was $8 million , which is expected to be recognized over a weighted average period of 1.5 years. Restricted Stock Awards The following is a summary of restricted stock award activity of our common stock in 2016 : Shares of Restricted Stock (“RS”) Restricted Stock Units (“RSU”) Number of Shares Weighted Average Grant Date Fair Value Number of Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2015 1,074,543 $ 47.70 513,220 $ 24.59 Granted 732,074 36.17 45,495 40.85 RS’s Vested/RSU’s Issued (477,339 ) 46.26 (197,598 ) 21.62 Forfeited (78,935 ) 47.53 — — Outstanding at December 31, 2016 1,250,343 41.51 361,117 28.26 Of the 361,117 restricted stock units outstanding, 343,327 are vested and have a weighted average grant date fair value of $27.25 . These vested but unissued units are held by our non-employee directors and certain officers, are non-forfeitable and are issuable upon the director’s departure from our board of directors or officers end of employment with the company. The following is a summary of the values related to restricted stock and restricted stock unit awards held by MPC employees and non-employee directors: Restricted Stock Restricted Stock Units Intrinsic Value of Awards Vested During the Period (in millions) Weighted Average Grant Date Fair Value of Awards Granted During the Period Intrinsic Value of Awards Vested During the Period (in millions) Weighted Average Grant Date Fair Value of Awards Granted During the Period 2016 $ 17 $ 36.17 $ 8 $ 40.85 2015 27 50.64 21 49.87 2014 28 43.82 — 42.95 As of December 31, 2016 , unrecognized compensation cost related to restricted stock awards was $34 million , which is expected to be recognized over a weighted average period of 1.5 years. There was no material unrecognized compensation cost related to restricted stock unit awards. Performance Unit Awards The following table presents a summary of the 2016 activity for performance unit awards to be settled in shares: Number of Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2015 6,145,442 $ 0.92 Granted 2,329,500 0.57 Exercised (1,904,792 ) 0.95 Canceled (314,972 ) 0.93 Outstanding at December 31, 2016 6,255,178 0.78 The number of shares that would be issued upon target vesting, using the closing price of our common stock on December 31, 2016 would be 124,234 shares. As of December 31, 2016 , unrecognized compensation cost related to equity-classified performance unit awards was $2 million , which is expected to be recognized over a weighted average period of 1.5 years. Performance units paying out in units have a grant date fair value calculated using a Monte Carlo valuation model, which requires the input of subjective assumptions. The following table provides a summary of these assumptions: 2016 2015 2014 Risk-free interest rate 0.96 % 0.95 % 0.63 % Look-back period 2.83 years 2.84 years 2.84 years Expected volatility 34.15 % 30.38 % 38.51 % Grant date fair value of performance units granted $ 0.57 $ 0.95 $ 0.85 The risk-free interest rate for the remaining performance period as of the grant date is based on the U.S. Treasury yield curve in effect at the time of the grant. The look-back period reflects the remaining performance period at the grant date. The assumption for the expected volatility of our stock price reflects the average MPC common stock historical volatility. MPLX Awards Our wholly-owned subsidiary and the general partner of MPLX, MPLX GP LLC (“MPLX GP”), maintains a unit-based compensation plan for officers, directors and employees (including any other individual who may be considered an “employee” under a Registration Statement on Form S-8 or any successor form) of MPLX GP. The MPLX 2012 Incentive Compensation Plan (“MPLX Plan”) permits various types of equity awards including but not limited to grants of phantom units and performance units. Awards granted under the MPLX Plan will be settled with MPLX units. Compensation expense for these awards were not material to our consolidated financial statements for the years ended December 31, 2016 , 2015 and 2014 .

Leases

Leases	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Leases of Lessee Disclosure	Lessee We lease a wide variety of facilities and equipment under operating leases, including land and building space, office equipment, storage facilities and transportation equipment. Most long-term leases include renewal options and, in certain leases, purchase options. Future minimum commitments as of December 31, 2016 , for capital lease obligations and for operating lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows: (In millions) Capital Lease Obligations Operating Lease Obligations 2017 $ 50 $ 254 2018 50 211 2019 45 198 2020 49 188 2021 45 170 Later years 206 569 Total minimum lease payments 445 $ 1,590 Less imputed interest costs 126 Present value of net minimum lease payments $ 319 Operating lease rental expense was: (In millions) 2016 2015 2014 Rental expense $ 327 $ 331 $ 256
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 US 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 2023 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 2030. Our revenue from implicit lease arrangements, excluding executory costs, totaled approximately $246 million , $16 million and $0 million in 2016 , 2015 and 2014 , respectively. 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 year ended December 31, 2016 , we received $7 million in contingent lease payments and less than $1 million for the year ended December 31, 2015 . The following is a schedule of minimum future rentals on the non‑cancellable operating leases as of December 31, 2016 : (In millions) 2017 $ 197 2018 200 2019 202 2020 201 2021 185 Later years 460 Total minimum lease payments $ 1,445 The following schedule summarizes our investment in assets held for operating lease by major classes as of December 31, 2016 : (In millions) Natural gas gathering and NGL transportation pipelines and facilities $ 650 Natural gas processing facilities 844 Construction in progress 219 Property, plant and equipment 1,713 Less accumulated depreciation 84 Total property, plant and equipment $ 1,629

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies We are the subject of, or a party to, a number of pending or threatened legal actions, contingencies and commitments involving a variety of matters, including laws and regulations relating to the environment. Some of these matters are discussed below. For matters for which we have not recorded an accrued liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings and discovery. However, the ultimate resolution of some of these contingencies could, individually or in the aggregate, be material. Environmental matters – We are subject to federal, state, local and foreign laws and regulations relating to the environment. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation of hazardous waste disposal sites and certain other locations including presently or formerly owned or operated retail marketing sites. Penalties may be imposed for noncompliance. At December 31, 2016 and 2015 , accrued liabilities for remediation totaled $132 million and $163 million . 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 $58 million and $70 million at December 31, 2016 and 2015 , respectively. We are involved in a number of environmental enforcement matters arising in the ordinary course of business. While the outcome and impact on us cannot be predicted with certainty, management believes the resolution of these environmental matters will not, individually or collectively, have a material adverse effect on our consolidated results of operations, financial position or cash flows. MarkWest Environmental Proceeding – In July 2015, representatives from the EPA and the United States Department of Justice conducted a raid on a pipeline launcher/receiver site of MarkWest Liberty Midstream & Resources, L.L.C., a wholly-owned subsidiary of MPLX (“MarkWest Liberty Midstream”), utilized for pipeline maintenance operations in Washington County, Pennsylvania pursuant to a search warrant issued by a magistrate of the United States District Court for the Western District of Pennsylvania. As part of this initiative, the U.S. Attorney’s Office for the Western District of Pennsylvania, with the assistance of EPA’s Criminal Investigation Division proceeded with an investigation of MarkWest’s launcher/receiver, pipeline and compressor station operations. In response to the investigation, MarkWest initiated independent studies which demonstrated that there was no risk to worker safety and no threat of public harm associated with MarkWest’s launcher/receiver operations. These findings were supported by a subsequent inspection and review by the Occupational Safety and Health Administration. After providing these studies, and other substantial documentation related to MarkWest's pipeline and compressor stations, and arranging site visits and conducting several meetings with the government’s representatives, on September 13, 2016, the U.S. Attorney’s Office for the Western District of Pennsylvania rendered a declination decision, dropping its criminal investigation and declining to pursue charges in this matter. MarkWest Liberty Midstream continues to discuss with the EPA and the State of Pennsylvania civil enforcement allegations associated with permitting or other related regulatory obligations for its launcher/receiver and compressor station facilities in the region. In connection with these discussions, MarkWest Liberty Midstream received an initial proposal from the EPA to settle all civil claims associated with this matter for the combination of a proposed cash penalty of approximately $2.4 million and proposed supplemental environmental projects with an estimated cost of approximately $3.6 million . MarkWest Liberty Midstream will be submitting a response asserting that this action involves novel issues surrounding primarily minor source emissions from facilities that the agencies themselves considered de minimis were not the subject of regulation and consequently that the settlement proposal is excessive. MarkWest will continue to negotiate with the EPA regarding the amount and scope of the proposed settlement. Other Lawsuits – In May 2015, the Kentucky attorney general filed a lawsuit against our wholly-owned subsidiary, 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 early stage, the ultimate outcome of this litigation remains uncertain, and neither the likelihood of an unfavorable outcome nor the ultimate liability, if any, can be determined, and we are unable to estimate a reasonably possible loss (or range of loss) for this matter. We intend to vigorously defend ourselves in this matter. In May 2007, the Kentucky attorney general filed a lawsuit against us and Marathon Oil in state court in Franklin County, Kentucky for alleged violations of Kentucky’s emergency pricing and consumer protection laws following Hurricanes Katrina and Rita in 2005. The lawsuit alleges that we overcharged customers by $89 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. We are also a party to a number of other lawsuits and other proceedings arising in the ordinary course of business. While the ultimate outcome and impact to us cannot be predicted with certainty, we believe that the resolution of these other lawsuits and proceedings will not have a material adverse effect on our consolidated financial position, results of operations or cash flows. Guarantees – We have provided certain guarantees, direct and indirect, of the indebtedness of other companies. Under the terms of most of these guarantee arrangements, we would be required to perform should the guaranteed party fail to fulfill its obligations under the specified arrangements. In addition to these financial guarantees, we also have various performance guarantees related to specific agreements. Guarantees related to indebtedness of equity method investees – We hold interests in an offshore oil port, LOOP, and a crude oil pipeline system, LOCAP. Both LOOP and LOCAP have secured various project financings with throughput and deficiency agreements. Under the agreements, we are required to advance funds if the investees are unable to service their debt. Any such advances are considered prepayments of future transportation charges. The duration of the agreements vary but tend to follow the terms of the underlying debt, which extend through 2037 . Our maximum potential undiscounted payments under these agreements for the debt principal totaled $172 million as of December 31, 2016 . We hold an interest in a refined products pipeline through our investment in Centennial, and have guaranteed our portion of the payment of Centennial’s principal, interest and prepayment costs, if applicable, under a Master Shelf Agreement, which is scheduled to expire in 2024 . The guarantee arose in order for Centennial to obtain adequate financing. Our maximum potential undiscounted payments under this agreement for debt principal totaled $29 million as of December 31, 2016 . In connection with our 50 percent ownership 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 December 31, 2016 , our maximum potential undiscounted payments under this agreement for debt principal totaled $163 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. The maximum exposure under these arrangements is 50 percent of the amount of the debt, which was $142 million as of December 31, 2016 . Marathon Oil indemnifications – In conjunction with the Spinoff, we have entered into arrangements with Marathon Oil providing indemnities and guarantees with recorded values of $2 million as of December 31, 2016 , which consist of unrecognized tax benefits related to MPC, its consolidated subsidiaries and the RM&T Business operations prior to the Spinoff which are not already reflected in the unrecognized tax benefits described in Note 12 , 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 the Spinoff provide for cross-indemnities between Marathon Oil and us. In general, Marathon Oil is required to indemnify us for any liabilities relating to Marathon Oil’s historical oil and gas exploration and production operations, oil sands mining operations and integrated gas operations, and we are required to indemnify Marathon Oil for any liabilities relating to Marathon Oil’s historical refining, marketing and transportation operations. The terms of these indemnifications are indefinite and the amounts are not capped. Other guarantees – We have entered into other guarantees with maximum potential undiscounted payments totaling $82 million as of December 31, 2016 , which consist primarily of a commitment to contribute cash to an equity method investee for certain catastrophic events, up to $50 million per event, in lieu of procuring insurance coverage and leases of assets containing general lease indemnities and guaranteed residual values. General guarantees associated with dispositions – Over the years, we have sold various assets in the normal course of our business. Certain of the related agreements contain performance and general guarantees, including guarantees regarding inaccuracies in representations, warranties, covenants and agreements, and environmental and general indemnifications that require us to perform upon the occurrence of a triggering event or condition. These guarantees and indemnifications are part of the normal course of selling assets. We are typically not able to calculate the maximum potential amount of future payments that could be made under such contractual provisions because of the variability inherent in the guarantees and indemnities. Most often, the nature of the guarantees and indemnities is such that there is no appropriate method for quantifying the exposure because the underlying triggering event has little or no past experience upon which a reasonable prediction of the outcome can be based. Contractual commitments and contingencies – At December 31, 2016 and 2015 , our contractual commitments to acquire property, plant and equipment and advance funds to equity method investees totaled $899 million and $1.6 billion . The contractual commitments at December 31, 2016 includes $131 million of contingent consideration associated with the acquisition of the Galveston Bay Refinery and Related Assets. The contractual commitments at December 31, 2015 included the $331 million contingent consideration associated with the acquisition of the Galveston Bay Refinery and Related Assets, $630 million for contributions to North Dakota Pipeline and $69 million for contributions to Crowley Ocean Partners. See Note 17 for additional information on the contingent consideration. 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 if there are significant delays that are not due to force majeure. As of December 31, 2016 , management does not believe there are any indications that we will not be able to meet the construction milestones, that force majeure does not apply, or that such fees and charges will otherwise be triggered.

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events On February 6, 2017, MPLX announced that its wholly-owned subsidiary, MarkWest, and Antero Midstream Partners L.P. (“Antero Midstream”) formed a strategic joint venture, Sherwood Midstream LLC, to support the development of Antero Resources Corporation’s extensive Marcellus Shale acreage in the prolific rich-gas corridor of West Virginia. In connection with this transaction, MarkWest contributed approximately $134 million of assets currently under construction at the Sherwood Complex and Antero Midstream made an initial capital contribution of approximately $154 million . On February 10, 2017, MPLX completed a public offering of $1.25 billion aggregate principal amount of 4.125% unsecured senior notes due March 2027 and $1.0 billion aggregate principal amount of 5.200% unsecured senior notes due March 2047. MPLX intends to use the net proceeds from this offering for general partnership purposes, which may include, from time to time, acquisitions (including the previously announced planned dropdown of assets from MPC) and capital expenditures. On February 13, 2017, MPLX announced that it had entered into an asset purchase agreement with Enbridge Pipelines (Ozark) LLC (“Enbridge Ozark”), under which an affiliate of Pipe Line Holdings has agreed to purchase the Ozark pipeline for approximately $220 million from Enbridge Ozark. The Ozark pipeline is a 433 -mile, 22 -inch crude oil pipeline originating in Cushing, Oklahoma, and terminating in Wood River, Illinois, capable of transporting approximately 230 mbpd. The purchase transaction is expected to close in the first quarter of 2017, subject to customary closing conditions, including regulatory approvals.

Selected Quarterly Financial Da

Selected Quarterly Financial Data	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Selected Quarterly Financial Data	Selected Quarterly Financial Data (Unaudited) 2016 2015 (In millions, except per share data) 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Revenues $ 12,755 $ 16,811 $ 16,618 $ 17,155 $ 17,191 $ 20,537 $ 18,716 $ 15,607 Income from operations 75 1,315 435 553 1,470 1,335 1,549 338 Net income (loss) (78 ) 783 219 289 903 839 958 168 Net income attributable to MPC 1 801 145 227 891 826 948 187 Net income attributable to MPC per share: (a) Basic $ 0.003 $ 1.51 $ 0.28 $ 0.43 $ 1.63 $ 1.52 $ 1.77 $ 0.35 Diluted 0.003 1.51 0.27 0.43 1.62 1.51 1.76 0.35 Dividends paid per share 0.32 0.32 0.36 0.36 0.25 0.25 0.32 0.32 (a) We completed a two-for-one stock split in June 2015. All historical per share data has been retroactively restated on a post-split basis.

Supplementary Statistics

Supplementary Statistics	12 Months Ended
	Dec. 31, 2016
Text Block [Abstract]
Supplementary Statistics	Supplementary Statistics (Unaudited) (In millions) 2016 2015 2014 Income from Operations by segment Refining & Marketing (a) $ 1,543 $ 4,086 $ 3,538 Speedway (a) 734 673 544 Midstream (b) 871 380 342 Items not allocated to segments: Corporate and other unallocated items (b) (277 ) (299 ) (277 ) Pension settlement expenses (7 ) (4 ) (96 ) Impairment (c) (486 ) (144 ) — Income from operations $ 2,378 $ 4,692 $ 4,051 Capital Expenditures and Investments (d)(e) Refining & Marketing $ 1,101 $ 1,045 $ 1,043 Speedway 303 501 2,981 Midstream 1,521 14,545 604 Corporate and Other (f) 144 192 110 Total $ 3,069 $ 16,283 $ 4,738 (a) In 2016, the Refining & Marketing and Speedway segments include an inventory LCM benefit of $345 million and $25 million , respectively. In 2015, the Refining & Marketing and Speedway segments include an inventory LCM charge of $345 million and $25 million , respectively. (b) Included in the Midstream segment for 2016 , 2015 and 2014 are $11 million , $20 million and $19 million of corporate overhead expenses attributable to MPLX. The remaining corporate overhead expenses are not currently allocated to other segments, but instead reported in corporate and other unallocated items. (c) 2016 relates to impairments of goodwill and equity method investments. 2015 relates to the cancellation of the Residual Oil Upgrader Expansion project. See Notes 15 , 16 and 17 to the audited consolidated financial statements. (d) Capital expenditures include changes in capital accruals. (e) Includes $13.85 billion in 2015 for the MarkWest Merger and $2.71 billion in 2014 for the acquisition of Hess’ Retail Operations and Related Assets. See Note 5 . (f) Includes capitalized interest of $63 million , $37 million and $27 million for 2016 , 2015 and 2014 , respectively. Supplementary Statistics (Unaudited) 2016 2015 2014 MPC Consolidated Refined Product Sales Volumes (mbpd) (a) 2,269 2,301 2,138 Refining & Marketing Operating Statistics Refining & Marketing refined product sales volume (mbpd) (b) 2,259 2,289 2,125 Refining & Marketing gross margin (dollars per barrel) (c)(d) $ 11.26 $ 15.25 $ 15.05 Crude oil capacity utilization percent (e) 95 99 95 Refinery throughputs (mbpd): (f) Crude oil refined 1,699 1,711 1,622 Other charge and blendstocks 151 177 184 Total 1,850 1,888 1,806 Sour crude oil throughput percent 60 55 52 WTI-priced crude oil throughput percent 19 20 19 Refined product yields (mbpd): (f) Gasoline 900 913 869 Distillates 617 603 580 Propane 35 36 35 Feedstocks and special products 241 281 276 Heavy fuel oil 32 31 25 Asphalt 58 55 54 Total 1,883 1,919 1,839 Refinery direct operating costs (dollars per barrel): (g) Planned turnaround and major maintenance $ 1.83 $ 1.13 $ 1.80 Depreciation and amortization 1.47 1.39 1.41 Other manufacturing (h) 4.09 4.15 4.86 Total $ 7.39 $ 6.67 $ 8.07 Refining & Marketing Operating Statistics By Region – Gulf Coast Refinery throughputs (mbpd): (i) Crude oil refined 1,039 1,060 991 Other charge and blendstocks 195 184 182 Total 1,234 1,244 1,173 Sour crude oil throughput percent 73 68 64 WTI-priced crude oil throughput percent 8 6 3 Refined product yields (mbpd): (i) Gasoline 514 534 508 Distillates 399 392 368 Propane 26 26 23 Feedstocks and special products 286 286 274 Heavy fuel oil 21 15 13 Asphalt 15 16 13 Total 1,261 1,269 1,199 Refinery direct operating costs (dollars per barrel): (g) Planned turnaround and major maintenance $ 2.09 $ 0.81 $ 1.82 Depreciation and amortization 1.14 1.09 1.15 Other manufacturing (h) 3.70 3.88 4.73 Total $ 6.93 $ 5.78 $ 7.70 Supplementary Statistics (Unaudited) 2016 2015 2014 Refining & Marketing Operating Statistics By Region – Midwest Refinery throughputs (mbpd): (i) Crude oil refined 660 651 631 Other charge and blendstocks 39 39 45 Total 699 690 676 Sour crude oil throughput percent 40 34 33 WTI-priced crude oil throughput percent 38 43 44 Refined product yields (mbpd): (i) Gasoline 386 379 361 Distillates 218 211 212 Propane 11 12 13 Feedstocks and special products 35 38 43 Heavy fuel oil 12 17 13 Asphalt 43 39 41 Total 705 696 683 Refinery direct operating costs (dollars per barrel): (g) Planned turnaround and major maintenance $ 1.15 $ 1.64 $ 1.66 Depreciation and amortization 1.88 1.83 1.78 Other manufacturing (h) 4.29 4.36 4.76 Total $ 7.32 $ 7.83 $ 8.20 Speedway Operating Statistics (j) Convenience stores at period-end (k) 2,733 2,766 2,746 Gasoline and distillate sales (millions of gallons) 6,094 6,038 3,942 Gasoline & distillate gross margin (dollars per gallon) (d)(l) $ 0.1656 $ 0.1823 $ 0.1775 Merchandise sales (in millions) $ 5,007 $ 4,879 $ 3,611 Merchandise gross margin (in millions) $ 1,435 $ 1,368 $ 975 Merchandise gross margin percent 28.7 % 28.0 % 27.0 % Same store gasoline sales volume (period over period) (0.4 )% (0.3 )% (0.7 )% Same store merchandise sales (period over period) (m) 3.2 % 4.1 % 5.0 % Midstream Operating Statistics Crude oil and refined product pipeline throughputs (mbpd) (n) 2,311 2,191 2,119 Gathering system throughput (MMcf/d) (o) 3,275 3,075 Natural gas processed (MMcf/d) (o) 5,761 5,468 C2 (ethane) + NGLs (natural gas liquids) fractionated (mbpd) (o) 335 307 (a) Total average daily volumes of refined product sales to wholesale, branded and retail customers. (b) Includes intersegment sales. (c) Sales revenue less cost of refinery inputs and purchased products, divided by total refinery throughputs. (d) Excludes the lower of cost or market adjustment. (e) Based on calendar day capacity, which is an annual average that includes downtime for planned maintenance and other normal operating activities. (f) Excludes inter-refinery volumes of 83 mbpd, 46 mbpd and 43 mbpd for 2016 , 2015 and 2014 , respectively. (g) Per barrel of total refinery throughputs. (h) Includes utilities, labor, routine maintenance and other operating costs. (i) Includes inter-refinery transfer volumes. (j) Includes the impact of Hess’ Retail Operations and Related Assets from the September 30, 2014 acquisition date. (k) Decrease in 2016 was primarily due to the contribution of 41 travel centers to the Pilot joint venture. (l) The price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, divided by gasoline and distillate sales volume. (m) Excludes cigarettes. (n) On owned common-carrier pipelines, excluding equity method investments. (o) Includes the results of the MarkWest assets beginning on the Dec. 4, 2015 acquisition date.Includes amounts related to unconsolidated equity method investments on a 100% basis.

Summary Of Principal Accounti40

Summary Of Principal Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Principles applied in consolidation	Principles applied in consolidation – These consolidated financial statements include the accounts of our majority-owned, controlled subsidiaries and MPLX. Changes in ownership interest in consolidated subsidiaries that do not result in a change in control are recorded as an equity transaction. As of December 31, 2016 , we owned a 25.5 percent interest in MPLX, including a two percent general partner interest. This ownership percentage reflects the conversion of the MPLX Class B Units in July 2017 at 1.09 to 1.00. Due to our 100 percent ownership of the general partner interest, we have determined that we control MPLX and therefore we consolidate MPLX and record a noncontrolling interest for the 74.5 percent interest owned by the public. Investments in entities over which we have significant influence, but not control, are accounted for using the equity method of accounting. This includes entities in which we hold majority ownership but the minority shareholders have substantive participating rights. Income from equity method investments represents our proportionate share of net income generated by the equity method investees. Differences in the basis of the investments and the separate net asset values of the investees, if any, are amortized into net income over the remaining useful lives of the underlying assets and liabilities, except for the excess related to goodwill. Equity method investments are evaluated for impairment whenever changes in the facts and circumstances indicate an other than temporary loss in value has occurred. When the loss is deemed to be other than temporary, the carrying value of the equity method investment is written down to fair value, and the amount of the write-down is included in net income.
Use of estimates	Use of estimates – The preparation of financial statements in accordance with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the respective reporting periods.
Revenue recognition	Revenue recognition – Revenues are recognized when products are shipped or services are provided to customers, title is transferred, the sales price is fixed or determinable and collectability is reasonably assured. Costs associated with revenues are recorded in cost of revenues. Shipping and other transportation costs billed to our customers are presented on a gross basis in revenues and cost of revenues. Rebates from vendors are recognized as a reduction of cost of revenues when the initiating transaction occurs. Incentives that are derived from contractual provisions are accrued based on past experience and recognized in cost of revenues. Rebates to customers are reflected as a reduction of revenue and are accrued for in “Accounts payable” on the consolidated balance sheets.
Crude oil and refined product exchanges and matching buy/sell transactions	Crude oil and refined product exchanges and matching buy/sell transactions – We enter into exchange contracts and matching buy/sell arrangements whereby we agree to deliver a particular quantity and quality of crude oil or refined products at a specified location and date to a particular counterparty and to receive from the same counterparty the same commodity at a specified location on the same or another specified date. The exchange receipts and deliveries are nonmonetary transactions, with the exception of associated grade or location differentials that are settled in cash. The matching buy/sell purchase and sale transactions are settled in cash. Both exchange and matching buy/sell transactions are accounted for as exchanges of inventory and no revenues are recorded. The exchange transactions are recognized at the carrying amount of the inventory transferred.
Consumer excise taxes	Consumer excise taxes – We are required by various governmental authorities, including countries, states and municipalities, to collect and remit taxes on certain consumer products. Such taxes are presented on a gross basis in revenues and costs and expenses in the consolidated statements of income.
Cash and cash equivalents	Cash and cash equivalents – Cash and cash equivalents include cash on hand and on deposit and investments in highly liquid debt instruments with maturities of three months or less.
Restricted cash	Restricted cash – Restricted cash consists of cash and investments that must be maintained as collateral for letters of credit issued to certain third party producer customers. The balances will be outstanding until certain capital projects are completed and the third party releases the restriction. Restricted cash also consists of cash advances to be used for the operation and maintenance of an operated pipeline system. At December 31, 2016 and 2015 , the amount of restricted cash included in “Other current assets” on the consolidated balance sheets were $5 million and $9 million , respectively, which is currently reflected in our Midstream segment
Accounts receivable and allowance for doubtful accounts	Accounts receivable and allowance for doubtful accounts – Our receivables primarily consist of customer accounts receivable. Customer receivables are recorded at the invoiced amounts and generally do not bear interest. Allowances for doubtful accounts are generally recorded when it becomes probable the receivable will not be collected and are booked to bad debt expense. The allowance for doubtful accounts is the best estimate of the amount of probable credit losses in customer accounts receivable. We review the allowance quarterly and past-due balances over 180 days are reviewed individually for collectability. Approximately 23 percent and 26 percent of our accounts receivable balances at December 31, 2016 and 2015 , respectively, are related to sales of crude oil or refinery feedstocks to customers with whom we have master netting agreements. We have master netting agreements with more than 100 companies engaged in the crude oil or refinery feedstock trading and supply business or the petroleum refining industry. A master netting agreement generally provides for a once per month net cash settlement of the accounts receivable from and the accounts payable to a particular counterparty.
Inventories	Inventories – Inventories are carried at the lower of cost or market value. Cost of inventories is determined primarily under the LIFO method. Costs for crude oil, refinery feedstocks and refined product inventories are aggregated on a consolidated basis for purposes of assessing if the LIFO cost basis of these inventories may have to be written down to market value.
Derivative instruments	Derivative instruments – We use derivatives to economically hedge a portion of our exposure to commodity price risk and, historically, to interest rate risk. We also have limited authority to use selective derivative instruments that assume market risk. All derivative instruments (including derivative instruments embedded in other contracts) are recorded at fair value. Certain commodity derivatives are reflected on the consolidated balance sheets on a net basis by counterparty as they are governed by master netting agreements. Cash flows related to derivatives used to hedge commodity price risk and interest rate risk are classified in operating activities with the underlying transactions. Fair value accounting hedges – We used interest rate swaps to hedge our exposure to interest rate risk associated with fixed interest rate debt in our portfolio. These interest rate swap agreements were terminated in 2012. Changes in the fair values of both the hedged item and the related derivative were recognized immediately in net income with an offsetting effect included in the basis of the hedged item. The net effect was to report in net income the extent to which the accounting hedge was not effective in achieving offsetting changes in fair value. There was a gain on the termination of the agreements, which had been deferred and accounted for as an adjustment to our long-term debt balance. The gain was being amortized over the remaining life of the associated debt as a reduction of our interest expense, until the December 2015 extinguishment of our obligation for the associated debt. At such time, the remaining unamortized gain was credited to net interest and other financial income (costs). Derivatives not designated as accounting hedges – 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, (6) the purchase of natural gas and (7) the purchase of electricity. Changes in the fair value of derivatives not designated as accounting hedges are recognized immediately in net income. Concentrations of credit risk – All of our financial instruments, including derivatives, involve elements of credit and market risk. The most significant portion of our credit risk relates to nonperformance by counterparties. The counterparties to our financial instruments consist primarily of major financial institutions and companies within the energy industry. To manage counterparty risk associated with financial instruments, we select and monitor counterparties based on an assessment of their financial strength and on credit ratings, if available. Additionally, we limit the level of exposure with any single counterparty.
Property, plant and equipment	Property, plant and equipment – Property, plant and equipment are recorded at cost and depreciated on a straight-line basis over the estimated useful lives of the assets, which range from two to 42 years. Such assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the expected undiscounted future cash flows from the use of the asset and its eventual disposition is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset. When items of property, plant and equipment are sold or otherwise disposed of, any gains or losses are reported in net income. Gains on the disposal of property, plant and equipment are recognized when earned, which is generally at the time of closing. If a loss on disposal is expected, such losses are recognized when the assets are classified as held for sale. Interest expense is capitalized for qualifying assets under construction. Capitalized interest costs are included in property, plant and equipment and are depreciated over the useful life of the related asset.
Goodwill and intangible assets	Goodwill and intangible assets – Goodwill represents the excess of the purchase price over the estimated fair value of the net assets acquired in the acquisition of a business. Goodwill is not amortized, but rather is tested for impairment annually and when events or changes in circumstances indicate that the fair value of a reporting unit with goodwill has been reduced below carrying value. The impairment test requires allocating goodwill and other assets and liabilities to reporting units. The fair value of each reporting unit is determined and compared to the carrying value of the reporting unit. If the fair value of the reporting unit is less than the carrying value, including goodwill, the implied fair value of goodwill is calculated. The excess, if any, of the book value over the implied fair value of goodwill is charged to net income as an impairment expense. Amortization of intangibles with definite lives is calculated using the straight-line method which is reflective of the benefit pattern in which the estimated economic benefit is expected to be received over the estimated useful life of the intangible asset. Intangibles subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the intangible may not be recoverable. If the sum of the expected undiscounted future cash flows related to the asset is less than the carrying amount of the asset, an impairment loss is recognized based on the fair value of the asset. Intangibles not subject to amortization are tested for impairment annually and when circumstances indicate that the fair value is less than the carrying amount of the intangible. If the fair value is less than the carrying value, an impairment is recorded for the difference.
Major maintenance activities	Major maintenance activities – Costs for planned turnaround, major maintenance and engineered project activities are expensed in the period incurred. These types of costs include contractor repair services, materials and supplies, equipment rentals and our labor costs.
Environmental costs	Environmental costs – Environmental expenditures are capitalized for additional equipment that mitigates or prevents future contamination or improves environmental safety or efficiency of the existing assets. We recognize remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs can be reasonably estimated. The timing of remediation accruals coincides with completion of a feasibility study or the commitment to a formal plan of action. Remediation liabilities are accrued based on estimates of known environmental exposure and are discounted when the estimated amounts are reasonably fixed and determinable. If recoveries of remediation costs from third parties are probable, a receivable is recorded and is discounted when the estimated amount is reasonably fixed and determinable.
Asset retirement obligations	Asset retirement obligations – The fair value of asset retirement obligations is recognized in the period in which the obligations are incurred if a reasonable estimate of fair value can be made. The majority of our recognized asset retirement liability relates to conditional asset retirement obligations for removal and disposal of fire-retardant material from certain refining facilities. The remaining recognized asset retirement liability relates to other refining assets, the removal of underground storage tanks at our leased convenience stores, certain pipelines and processing facilities and other related pipeline assets. The fair values recorded for such obligations are based on the most probable current cost projections. The recorded asset retirement obligations are not material to the consolidated financial statements. Asset retirement obligations have not been recognized for some assets because the fair value cannot be reasonably estimated since the settlement dates of the obligations are indeterminate. Such obligations will be recognized in the period when sufficient information becomes available to estimate a range of potential settlement dates. The asset retirement obligations principally include the hazardous material disposal and removal or dismantlement requirements associated with the closure of certain refining, terminal, retail, pipeline and processing assets. Our practice is to keep our assets in good operating condition through routine repair and maintenance of component parts in the ordinary course of business and by continuing to make improvements based on technological advances. As a result, we believe that generally these assets have no expected settlement date for purposes of estimating asset retirement obligations since the dates or ranges of dates upon which we would retire these assets cannot be reasonably estimated at this time.
Income taxes	Income taxes – Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their tax bases. Deferred tax assets are recorded when it is more likely than not that they will be realized. The realization of deferred tax assets is assessed periodically based on several factors, primarily our expectation to generate sufficient future taxable income.
Stock-based compensation arrangements	Stock-based compensation arrangements – The fair value of stock options granted to our employees is estimated on the date of grant using the Black-Scholes option pricing model. The model employs various assumptions, based on management’s estimates at the time of grant, which impact the calculation of fair value and ultimately, the amount of expense that is recognized over the vesting period of the stock option award. Of the required assumptions, the expected life of the stock option award and the expected volatility of our stock price have the most significant impact on the fair value calculation. The average expected life is based on our historical employee exercise behavior. The assumption for expected volatility of our stock price reflects a weighting of 50 percent of our common stock implied volatility and 50 percent of our common stock historical volatility. The fair value of restricted stock awards granted to our employees is determined based on the fair market value of our common stock on the date of grant. The fair value of performance unit awards granted to our employees is estimated on the date of grant using a Monte Carlo valuation model. Our stock-based compensation expense is recognized based on management’s estimate of the awards that are expected to vest, using the straight-line attribution method for all service-based awards with a graded vesting feature. If actual forfeiture results are different than expected, adjustments to recognized compensation expense may be required in future periods. Unearned stock-based compensation is charged to equity when restricted stock awards are granted. Compensation expense is recognized over the vesting period and is adjusted if conditions of the restricted stock award are not met.
Business combinations	Business combinations - We recognize and measure the assets acquired and liabilities assumed in a business combination based on their estimated fair values at the acquisition date, with any remaining difference versus the purchase consideration recorded as goodwill or gain from a bargain purchase. For all material acquisitions, management engages an independent valuation specialist to assist with the determination of fair value of the assets acquired, liabilities assumed, noncontrolling interest, if any, and goodwill, based on recognized business valuation methodologies. If the initial accounting for the business combination is incomplete by the end of the reporting period in which the acquisition occurs, an estimate will be recorded. Subsequent to the acquisition, and not later than one year from the acquisition date, we will record any material adjustments to the initial estimate based on new information obtained about facts and circumstances that existed as of the acquisition date. An income, market or cost valuation method may be utilized to estimate the fair value of the assets acquired, liabilities assumed, and noncontrolling interest, if any, in a business combination. The income valuation method represents the present value of future cash flows over the life of the asset using: (i) discrete financial forecasts, which rely on management’s estimates of revenue and operating expenses; (ii) long-term growth rates; and (iii) appropriate discount rates. The market valuation method uses prices paid for a reasonably similar asset by other purchasers in the market, with adjustments relating to any differences between the assets. The cost valuation method is based on the replacement cost of a comparable asset at prices at the time of the acquisition reduced for depreciation of the asset. Acquisition-related costs are expensed as incurred in connection with each business combination.
Renewable fuel identification numbers (RINs)	Renewable fuel identification numbers – We purchase RINs to satisfy a portion of our RFS2 compliance. We record a short-term intangible asset, included in “Other current assets” on the balance sheet, for RINs owned in excess of our anticipated current period compliance requirements. The asset value is based on the product of the excess RINs as of the balance sheet date, if any, and the average cost of our RINs. We record a current liability, included in “Other current liabilities” on the balance sheet, when we are deficient RINs based on the product of the deficient RINs as of the balance sheet date, if any, and the market price of the RINs at the balance sheet date. The cost of RINs used for compliance is reflected in “Cost of revenues” on the income statement. Any gains or losses on the sale or expiration of RINs are classified as “Other income” on the income statement. Proceeds from RIN sales are included in investing activities - “All other, net” on the cash flow statement.

MPLX LP (Tables)

MPLX LP (Tables)	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interest	Changes in MPC’s equity resulting from changes in its ownership interest in MPLX were as follows: (In millions) 2016 2015 Transfers (to) from noncontrolling interest Increase (decrease) in MPC's paid in capital for the issuance of MPLX LP common units to the public $ (60 ) $ 1,532 Increase in MPC's paid in capital for the issuance of MPLX LP common units and general partner units to MPC 121 — Net transfers (to) from noncontrolling interests 61 1,532 Tax impact (118 ) (404 ) Change in MPC's additional paid-in capital, net of tax $ (57 ) $ 1,128

Acquisitions and Investments (T

Acquisitions and Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Information	The following unaudited pro forma financial information presents consolidated results assuming the MarkWest Merger occurred on January 1, 2014 and the Hess’ Retail Operations and Related Assets acquisition occurred on January 1, 2013. (In millions, except per share data) 2015 2014 Sales and other operating revenues (including consumer excise taxes) $ 73,760 $ 108,605 Net income attributable to MPC 2,825 2,522 Net income attributable to MPC per share – basic $ 5.25 $ 4.42 Net income attributable to MPC per share – diluted 5.21 4.39
MarkWest
Business Acquisition [Line Items]
Components Of The Fair Value Of Consideration Transferred	The components of the fair value of consideration transferred are as follows: (In millions) Fair value of MPLX units issued $ 7,326 Cash payment to MarkWest unitholders 1,230 Payable to MarkWest Class B unitholders 50 Total fair value of consideration transferred $ 8,606
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the final purchase price allocation. Subsequent to December 31, 2015, additional analysis was completed and adjustments were made to the preliminary purchase price allocation as noted in the table below. The estimated fair value of assets acquired and liabilities and noncontrolling interests assumed at the acquisition date, are as follows: (In millions) As originally reported Adjustments As adjusted Cash and cash equivalents $ 12 $ — $ 12 Receivables 164 — 164 Inventories 33 (1 ) 32 Other current assets 44 — 44 Equity method investments 2,457 143 2,600 Property, plant and equipment, net 8,474 43 8,517 Other noncurrent assets (a) 473 65 538 Total assets acquired 11,657 250 11,907 Accounts payable 322 6 328 Payroll and benefits payable 13 — 13 Accrued taxes 21 — 21 Other current liabilities 44 — 44 Long-term debt 4,567 — 4,567 Deferred income taxes 374 3 377 Deferred credit and other liabilities 151 — 151 Noncontrolling interests 13 — 13 Total liabilities and noncontrolling interest assumed 5,505 9 5,514 Net assets acquired excluding goodwill 6,152 241 6,393 Goodwill 2,454 (241 ) 2,213 Net assets acquired $ 8,606 $ — $ 8,606 (a) The adjustment relates to acquired intangible assets.
Business Acquisition, Pro Forma Information	The amounts of revenue and income from operations associated with the MarkWest Merger included in our consolidated statements of income for 2015 are as follows: (In millions) 2015 Sales and other operating revenues (including consumer excise taxes) $ 120 Income from operations 32
Hess Retail Operations and Related Assets
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Information	The amounts of revenue and income from operations associated with Hess’ Retail Operations and Related Assets included in our consolidated statements of income for 2014 are as follows: (In millions) 2014 Sales and other operating revenues (including consumer excise taxes) $ 2,403 Income from operations 113

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Sales to Related Parties	Sales to related parties, which are included in “Sales and other operating revenues (including consumer excise taxes)” on the accompanying consolidated statements of income, were as follows: (In millions) 2016 2015 2014 PFJ Southeast $ 56 $ — $ — Other equity method investees 6 6 7 Total $ 62 $ 6 $ 7
Other Income From Related Parties	Other income from related parties, which is included in “Other income” on the accompanying consolidated statements of income, were as follows: (In millions) 2016 2015 2014 MarkWest Utica EMG $ 16 $ — $ — Ohio Condensate 4 — — Ohio Gathering 15 2 — Other equity method investees 6 2 1 Total $ 41 $ 4 $ 1 Other income from related parties consists primarily of fees received for operating transportation assets for our related parties.
Purchases From Related Parties	Purchases from related parties were as follows: (In millions) 2016 2015 2014 Crowley Blue Water Partners $ 37 $ — $ — Crowley Ocean Partners 52 6 — Explorer 14 20 39 Illinois Extension Pipeline 110 4 — LOCAP 23 23 21 LOOP 59 52 88 TAAE 41 52 79 TACE 59 54 121 TAME 93 87 141 Other equity method investees 21 10 16 Total $ 509 $ 308 $ 505
Receivables From Related Parties	Receivables from related parties, which are included in “Receivables, less allowance for doubtful accounts” on the accompanying consolidated balance sheets, were as follows: December 31, (In millions) 2016 2015 Centennial $ — $ 1 MarkWest Utica EMG 2 1 Ohio Condensate — 3 Ohio Gathering 2 5 PFJ Southeast 40 — Other equity method investees 1 3 Total $ 45 $ 13
Payables To Related Parties	Payables to related parties, which are included in “Accounts payable” on the accompanying consolidated balance sheets, were as follows: December 31, (In millions) 2016 2015 Explorer $ — $ 1 Illinois Extension Pipeline 9 4 LOCAP 2 2 LOOP 6 5 MarkWest Utica EMG 24 19 Ohio Condensate 1 4 TAAE 2 1 TACE 4 2 TAME 4 3 Other equity method investees 1 1 Total $ 53 $ 42

Income per Common Share (Tables

Income per Common Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Summary of Earnings Per Common Share	MPC grants certain incentive compensation awards to employees and non-employee directors that are considered to be participating securities. Due to the presence of participating securities, we have calculated our earnings per share using the two-class method. (In millions, except per share data) 2016 2015 2014 Basic earnings per share: Allocation of earnings: Net income attributable to MPC $ 1,174 $ 2,852 $ 2,524 Income allocated to participating securities 1 4 4 Income available to common stockholders – basic $ 1,173 $ 2,848 $ 2,520 Weighted average common shares outstanding 528 538 570 Basic earnings per share $ 2.22 $ 5.29 $ 4.42 Diluted earnings per share: Allocation of earnings: Net income attributable to MPC $ 1,174 $ 2,852 $ 2,524 Income allocated to participating securities 1 4 4 Income available to common stockholders – diluted $ 1,173 $ 2,848 $ 2,520 Weighted average common shares outstanding 528 538 570 Effect of dilutive securities 2 4 4 Weighted average common shares, including dilutive effect 530 542 574 Diluted earnings per share $ 2.21 $ 5.26 $ 4.39
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. (In millions) 2016 2015 2014 Shares issued under stock-based compensation plans 3 1 1

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Share Repurchases	Total share repurchases were as follows for the respective periods: (In millions, except per share data) 2016 2015 2014 Number of shares repurchased 4 19 49 Cash paid for shares repurchased $ 197 $ 965 $ 2,131 Effective average cost per delivered share $ 41.84 $ 50.31 $ 44.31

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Income From Operations Attributable To Operating Segments	(In millions) Refining & Marketing Speedway Midstream Total Year Ended December 31, 2016 Revenues: Customer $ 43,228 $ 18,283 $ 1,828 $ 63,339 Intersegment (a) 10,589 3 808 11,400 Segment revenues $ 53,817 $ 18,286 $ 2,636 $ 74,739 Segment income from operations (b)(c) $ 1,543 $ 734 $ 871 $ 3,148 Income from equity method investments (d) 24 5 142 171 Depreciation and amortization (d) 1,092 273 576 1,941 Capital expenditures and investments (e) 1,101 303 1,521 2,925 (In millions) Refining & Marketing Speedway Midstream Total Year Ended December 31, 2015 Revenues: Customer $ 52,174 $ 19,690 $ 187 $ 72,051 Intersegment (a) 12,024 3 777 12,804 Segment revenues $ 64,198 $ 19,693 $ 964 $ 84,855 Segment income from operations (b)(c) $ 4,086 $ 673 $ 380 $ 5,139 Income from equity method investments 26 — 62 88 Depreciation and amortization (d) 1,052 254 144 1,450 Capital expenditures and investments (e)(f) 1,045 501 14,545 16,091 (In millions) Refining & Marketing Speedway Midstream Total Year Ended December 31, 2014 Revenues: Customer $ 80,821 $ 16,927 $ 71 $ 97,819 Intersegment (a) 10,912 5 753 11,670 Segment revenues $ 91,733 $ 16,932 $ 824 $ 109,489 Segment income from operations (b) $ 3,538 $ 544 $ 342 $ 4,424 Income from equity method investments 96 — 57 153 Depreciation and amortization (d) 1,020 152 102 1,274 Capital expenditures and investments (e)(g) 1,043 2,981 604 4,628 (a) Management believes intersegment transactions were conducted under terms comparable to those with unaffiliated parties. (b) Included in the Midstream segment for 2016 , 2015 and 2014 are $11 million , $20 million and $19 million , respectively, of corporate overhead expenses attributable to MPLX. The remaining corporate overhead expenses are not currently allocated to other segments, but instead are reported in corporate and other unallocated items. Also included in the Midstream segment for 2015 are $36 million of transaction costs related to the MarkWest Merger. (c) In 2016, the Refining & Marketing and Speedway segments include an inventory LCM benefit of $345 million and $25 million , respectively. In 2015, the Refining & Marketing and Speedway segments include an inventory LCM charge of $345 million and $25 million , respectively. (d) Differences between segment totals and MPC totals represent amounts related to unallocated items and are included in “Items not allocated to segments” in the reconciliation below. (e) Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates. (f) The Midstream segment includes $13.85 billion for the MarkWest Merger. See Note 5 . (g) The Speedway and Refining & Marketing segments include $2.66 billion and $52 million , respectively, for the acquisition of Hess’ Retail Operations and Related Assets. See Note 5 .
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: (In millions) 2016 2015 2014 Segment income from operations $ 3,148 $ 5,139 $ 4,424 Items not allocated to segments: Corporate and other unallocated items (a) (277 ) (299 ) (277 ) Pension settlement expenses (b) (7 ) (4 ) (96 ) Impairments (c) (486 ) (144 ) — Net interest and other financial income (costs) (556 ) (318 ) (216 ) Income before income taxes $ 1,822 $ 4,374 $ 3,835 (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, which are included in the Midstream segment. Corporate overhead expenses are not allocated to the Refining & Marketing and Speedway segments. (b) See Note 22 . (c) 2016 includes impairments of goodwill and equity method investments. 2015 relates to the cancellation of the ROUX project at our Garyville refinery. See Notes 15 , 16 and 17 .
Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures	The following reconciles segment capital expenditures and investments to total capital expenditures: (In millions) 2016 2015 2014 Segment capital expenditures and investments $ 2,925 $ 16,091 $ 4,628 Less investments in equity method investees (a) 431 2,788 413 Plus items not allocated to segments: Corporate and Other 81 155 83 Capitalized interest 63 37 27 Total capital expenditures (b) $ 2,638 $ 13,495 $ 4,325 (a) 2016 includes an adjustment of $143 million to the fair value of equity method investments acquired in connection with the MarkWest Merger. 2015 includes $2.46 billion for the MarkWest Merger. See Note 5 . (b) Capital expenditures include changes in capital accruals. See Note 20 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.
Reconciliation Of Total Revenues To Sales And Other Operating Revenues	The following reconciles total segment customer revenues to sales and other operating revenues (including consumer excise taxes) as reported in the consolidated statements of income: (In millions) 2016 2015 2014 Customer revenues $ 63,339 $ 72,051 $ 97,819 Corporate and other unallocated items — — (2 ) Sales and other operating revenues (including consumer excise taxes) $ 63,339 $ 72,051 $ 97,817
Schedule Of Revenues By Product Line	Revenues by product line were: (In millions) 2016 2015 2014 Refined products $ 54,511 $ 63,744 $ 90,702 Merchandise 5,297 5,188 3,817 Crude oil and refinery feedstocks 2,038 2,718 2,917 Service, transportation and other 1,493 401 381 Sales and other operating revenues (including consumer excise taxes) $ 63,339 $ 72,051 $ 97,817
Total Assets by Reportable Segment	Total assets by reportable segment were: December 31, (In millions) 2016 2015 Refining & Marketing $ 18,039 $ 17,379 Speedway 5,426 5,349 Midstream 18,078 17,462 Corporate and Other 2,870 2,925 Total consolidated assets $ 44,413 $ 43,115

Other Items (Tables)

Other Items (Tables)	12 Months Ended
	Dec. 31, 2016
Other Income and Expenses [Abstract]
Net Interest And Other Financial Income (Costs)	Net interest and other financial income (costs) was: (In millions) 2016 2015 2014 Interest income $ 6 $ 6 $ 7 Interest expense (a) (602 ) (325 ) (229 ) Interest capitalized 64 37 27 Loss on extinguishment of debt — (5 ) — Other financial costs (b) (24 ) (31 ) (21 ) Net interest and other financial income (costs) $ (556 ) $ (318 ) $ (216 ) (a) 2016 and 2015 includes $44 million and $1 million , respectively, for the amortization of the discount related to the difference between the fair value and the principal amount of the assumed MarkWest debt. (b) 2015 includes $6 million of transaction costs related to the MarkWest Merger.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Components Of Income Tax Provisions (Benefits)	Income tax provisions (benefits) were: 2016 2015 2014 (In millions) Current Deferred Total Current Deferred Total Current Deferred Total Federal $ 189 $ 336 $ 525 $ 1,210 $ 134 $ 1,344 $ 1,382 $ (199 ) $ 1,183 State and local 27 57 84 152 9 161 135 (37 ) 98 Foreign (1 ) 1 — 10 (9 ) 1 5 (6 ) (1 ) Total $ 215 $ 394 $ 609 $ 1,372 $ 134 $ 1,506 $ 1,522 $ (242 ) $ 1,280
Reconciliation Of Federal Statutory Income Tax Rate	A reconciliation of the federal statutory income tax rate ( 35 percent ) applied to income before income taxes to the provision for income taxes follows: 2016 2015 2014 Statutory rate applied to income before income taxes 35 % 35 % 35 % State and local income taxes, net of federal income tax effects 3 2 2 Domestic manufacturing deduction (1 ) (2 ) (2 ) Noncontrolling interests (1 ) — — Biodiesel excise tax credit (1 ) (1 ) — Other (2 ) — (2 ) Provision for income taxes 33 % 34 % 33 %
Components Of Deferred Tax Assets And Liabilities	Deferred tax assets and liabilities resulted from the following: December 31, (In millions) 2016 2015 Deferred tax assets: Employee benefits $ 578 $ 631 Environmental 34 44 Net operating loss carryforwards 23 73 Other 58 73 Total deferred tax assets 693 821 Deferred tax liabilities: Property, plant and equipment 2,591 2,512 Inventories 707 579 Investments in subsidiaries and affiliates 1,145 909 Other 94 89 Total deferred tax liabilities 4,537 4,089 Net deferred tax liabilities $ 3,844 $ 3,268
Components Of Net Deferred Tax Liabilities Classified In Consolidated Balance Sheets	Net deferred tax liabilities were classified in the consolidated balance sheets as follows: December 31, (In millions) 2016 2015 Assets: Other noncurrent assets $ 17 $ 17 Liabilities: Deferred income taxes 3,861 3,285 Net deferred tax liabilities $ 3,844 $ 3,268
Summary Of Income Tax Returns Subject To Examination	As of December 31, 2016 , our income tax returns remain subject to examination in the following major tax jurisdictions for the tax years indicated: United States Federal 2010 - 2015 States 2008 - 2015
Summary Of Activity In Unrecognized Tax Benefits	The following table summarizes the activity in unrecognized tax benefits: (In millions) 2016 2015 2014 January 1 balance $ 12 $ 12 $ 13 Additions for tax positions of prior years 6 — 7 Reductions for tax positions of prior years (10 ) — (10 ) Settlements (1 ) — 2 December 31 balance $ 7 $ 12 $ 12

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Summary Of Inventories	December 31, (In millions) 2016 2015 Crude oil and refinery feedstocks $ 2,208 $ 2,180 Refined products 2,810 2,804 Materials and supplies 485 438 Merchandise 153 173 Lower of cost or market reserve — (370 ) Total $ 5,656 $ 5,225

Equity Method Investments (Tabl

Equity Method Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Schedule Of Equity Method Investments	Ownership as of Carrying value at December 31, December 31, (In millions) 2016 2016 2015 Centennial 50% $ 35 $ 37 Centrahoma Processing LLC 40% 104 111 Crowley Coastal Partners 50% 184 — Crowley Ocean Partners (a) 50% — 72 Explorer 25% 94 91 Illinois Extension Pipeline 35% 293 267 LOCAP 59% 22 22 LOOP 51% 277 243 MarkWest Utica EMG 56% 2,224 2,160 North Dakota Pipeline (b) 38% 30 287 Ohio Condensate (b) 60% 10 101 PFJ Southeast (c) 29% 283 — TAAE 45% 33 27 TACE 61% 33 49 TAEI 34% 15 18 TAME (d) 50% 18 27 Other MPLX investments 129 86 Other 43 24 Total $ 3,827 $ 3,622 (a) Crowley Ocean Partners merged into Crowley Coastal Partners in 2016. (b) During 2016, we recorded an impairment charge of $267 million related to our investment in North Dakota Pipeline and an impairment charge of $89 million related to our investment in Ohio Condensate. See Note 17 for additional information. (c) This joint venture with Pilot Flying J was formed in 2016. See Note 5 . (d) Excludes TAEI’s investment in TAME.
Summarized Financial Information For Equity Method Investees	Summarized financial information for equity method investees is as follows: (In millions) 2016 2015 2014 Income statement data: Revenues and other income $ 2,421 $ 1,390 $ 1,430 Income (loss) from operations (116 ) 332 379 Net income (loss) (250 ) 239 316 Balance sheet data – December 31: Current assets $ 711 $ 906 Noncurrent assets 8,170 6,418 Current liabilities 884 468 Noncurrent liabilities 1,462 1,130

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Summary Of Property, Plant And Equipment	(In millions) Estimated Useful Lives December 31, 2016 2015 Refining & Marketing 2 - 30 years $ 19,447 $ 18,396 Speedway 4 - 25 years 5,078 5,067 Midstream 3 - 42 years 12,664 11,379 Corporate and Other 4 - 40 years 817 762 Total 38,006 35,604 Less accumulated depreciation 12,241 10,440 Property, plant and equipment, net $ 25,765 $ 25,164

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill for 2016 and 2015 were as follows: (In millions) Refining & Marketing Speedway Midstream Total Balance at January 1, 2015 $ 539 $ 854 $ 173 $ 1,566 Acquisitions (a) — — 2,454 2,454 Disposition — (1 ) — (1 ) Balance at December 31, 2015 $ 539 $ 853 $ 2,627 $ 4,019 Purchase price allocation adjustments (a) — — (241 ) (241 ) Disposition (b) — (61 ) — (61 ) Impairment — — (130 ) (130 ) Balance at December 31, 2016 $ 539 $ 792 $ 2,256 $ 3,587 (a) See Note 5 for information on the acquisitions and purchase price allocation adjustments. (b) Goodwill associated with our former Speedway travel plaza locations that are now part of the PFJ Southeast joint venture. The amount was included in the initial basis for our equity method investment in the joint venture.
Schedule of Acquired Finite-Lived Intangible Assets by Major Class	Our intangible assets as of December 31, 2016 and 2015 are as follows: (In millions) Refining & Marketing Speedway Midstream Total Balance at December 31, 2016 Customer contracts and relationships $ 102 $ 1 $ 533 $ 636 Royalty agreements 128 — — 128 Favorable lease contract terms 1 57 — 58 Other (a) 27 75 — 102 Gross $ 258 $ 133 $ 533 $ 924 Accumulated amortization (123 ) (35 ) (41 ) (199 ) Net $ 135 $ 98 $ 492 $ 725 Balance at December 31, 2015 Customer contracts and relationships $ 91 $ 1 $ 468 $ 560 Royalty agreements 122 — — 122 Favorable lease contract terms 1 70 — 71 Other (a) 28 75 — 103 Gross $ 242 $ 146 $ 468 $ 856 Accumulated amortization (104 ) (31 ) (2 ) (137 ) Net $ 138 $ 115 $ 466 $ 719 (a) The Refining & Marketing and Speedway segments include unamortized intangible assets of $3 million and $46 million , respectively, which are primarily trademarks.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Estimated future amortization expense related to the intangible assets at December 31, 2016 is as follows: (In millions) 2017 $ 49 2018 49 2019 49 2020 48 2021 46

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 and 2015 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. December 31, 2016 Fair Value Hierarchy (In millions) Level 1 Level 2 Level 3 Netting and Collateral (a) Net Carrying Value on Balance Sheet (b) Collateral Pledged Not Offset Commodity derivative instruments, assets $ 688 $ — $ — $ (688 ) $ — $ 126 Other assets 2 — — N/A 2 — Total assets at fair value $ 690 $ — $ — $ (688 ) $ 2 $ 126 Commodity derivative instruments, liabilities $ 712 $ — $ 6 $ (712 ) $ 6 $ — Embedded derivatives in commodity contracts (c) — — 54 — 54 — Contingent consideration, liability (d) — — 130 N/A 130 — Total liabilities at fair value $ 712 $ — $ 190 $ (712 ) $ 190 $ — December 31, 2015 Fair Value Hierarchy (In millions) Level 1 Level 2 Level 3 Netting and Collateral (a) Net Carrying Value on Balance Sheet (b) Collateral Pledged Not Offset Commodity derivative instruments, assets $ 104 $ 2 $ 7 $ (62 ) $ 51 $ — Other assets 2 — — N/A 2 — Total assets at fair value $ 106 $ 2 $ 7 $ (62 ) $ 53 $ — Commodity derivative instruments, liabilities $ 39 $ — $ — $ (39 ) $ — $ — Embedded derivatives in commodity contracts (c) — — 32 $ — 32 — Contingent consideration, liability (d) — — 317 N/A 317 — Total liabilities at fair value $ 39 $ — $ 349 $ (39 ) $ 349 $ — (a) Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of December 31, 2016 , cash collateral of $24 million was netted with mark-to-market derivative liabilities. As of December 31, 2015 , cash collateral of $23 million was netted with mark-to-market derivative assets. (b) We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet. (c) Includes $13 million and $5 million classified as current as of December 31, 2016 and 2015 , respectively. (d) Includes $130 million and $196 million classified as current as of December 31, 2016 and 2015 , respectively.
Reconciliation of Net Beginning and Ending Balances Recorded for Net Assets and Liabilities Classified as Level 3	The following is a reconciliation of the net beginning and ending balances recorded for net assets and liabilities classified as Level 3 in the fair value hierarchy. (In millions) 2016 2015 2014 Beginning balance $ 342 $ 478 $ 625 Contingent consideration payment (a) (200 ) (189 ) (180 ) Net derivative positions assumed - MarkWest Merger — 31 — Unrealized and realized losses included in net income 55 20 33 Settlements of derivative instruments (7 ) 2 — Ending balance $ 190 $ 342 $ 478 The amount of total (gains) losses for the period included in earnings attributable to the change in unrealized (gains) losses relating to assets still held at the end of period: Derivative instruments $ 32 $ (7 ) $ — Contingent consideration agreement 13 28 33 Total $ 45 $ 21 $ 33 (a) On the consolidated statements of cash flows for 2016, 2015 and 2014, $164 million , $175 million and $172 million , respectively, of the contingent earnout payment to BP was included as a financing activity with the remainder included as an operating activity.
Assets Measured at Fair Value on a Nonrecurring Basis	The following table shows the values of assets, by major category, measured at fair value on a nonrecurring basis in periods subsequent to their initial recognition. Year Ended December 31, 2016 2015 2014 (In millions) Fair Value Impairment Fair Value Impairment Fair Value Impairment Equity method investments $ 42 $ 356 $ — $ — $ — $ — Goodwill — 130 — — — — Property, plant and equipment, net — — — 144 — — Other noncurrent assets — — — — — 11
Financial Instruments at Fair Value, Excluding Derivative Financial Instruments and Contingent Consideration	The following table summarizes financial instruments on the basis of their nature, characteristics and risk at December 31, 2016 and 2015 , excluding the derivative financial instruments and contingent consideration reported above. December 31, 2016 2015 (In millions) Fair Value Carrying Value Fair Value Carrying Value Financial assets: Investments $ 25 $ 2 $ 33 $ 2 Other 21 21 35 33 Total financial assets $ 46 $ 23 $ 68 $ 35 Financial liabilities: Long-term debt (a) $ 10,892 $ 10,297 $ 11,366 $ 11,628 Deferred credits and other liabilities 121 109 136 135 Total financial liabilities $ 11,013 $ 10,406 $ 11,502 $ 11,763 (a) Excludes capital leases and debt issuance costs, however, includes amount classified as debt due within one year.

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2016
Summary of Derivative Instruments [Abstract]
Classification of Fair Values of Derivative Instruments, Excluding Cash Collateral	The following table presents the gross fair values of derivative instruments, excluding cash collateral, and where they appear on the consolidated balance sheets as of December 31, 2016 and 2015 : (In millions) December 31, 2016 Balance Sheet Location Asset Liability Commodity derivatives Other current assets $ 688 $ 712 Other current liabilities (a) — 13 Deferred credits and other liabilities (a) — 47 (In millions) December 31, 2015 Balance Sheet Location Asset Liability Commodity derivatives Other current assets $ 113 $ 39 Other current liabilities (a) — 5 Deferred credits and other liabilities (a) — 27 (a) Includes embedded derivatives.
Open Commodity Derivative Contracts	The table below summarizes open commodity derivative contracts for crude oil and refined products as of December 31, 2016 . Position Total Barrels (In thousands) Crude Oil (a) Exchange-traded Long 53,028 Exchange-traded Short (52,373 ) OTC Short (37 ) (a ) 98.7 percent of the exchange-traded contracts expire in the first quarter of 2017 . Position MMbtu Natural Gas OTC Long 297,017 Position Total Gallons (In thousands) Refined Products (a) Exchange-traded Long 196,434 Exchange-traded Short (221,970 ) OTC Short (64,212 ) (a ) 100 percent of the exchange-traded contracts expire in the first quarter of 2017 .
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: (In millions) Gain (Loss) Income Statement Location 2016 2015 2014 Sales and other operating revenues $ (13 ) $ 19 $ 37 Cost of revenues (167 ) 294 456 Total $ (180 ) $ 313 $ 493

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Outstanding Borrowings	Our outstanding borrowings at December 31, 2016 and 2015 consisted of the following: December 31, (In millions) 2016 2015 Marathon Petroleum Corporation: Commercial paper $ — $ — 364-day bank revolving credit facility due July 2017 — — Trade receivables securitization facility due July 2019 — — Bank revolving credit facility due 2020 — — Term loan agreement due 2019 200 700 Senior notes, 2.700% due December 2018 600 600 Senior notes, 3.400% due December 2020 650 650 Senior notes, 5.125% due March 2021 1,000 1,000 Senior notes, 3.625%, due September 2024 750 750 Senior notes, 6.500%, due March 2041 1,250 1,250 Senior notes, 4.750%, due September 2044 800 800 Senior notes, 5.850% due December 2045 250 250 Senior notes, 5.000%, due September 2054 400 400 MPLX LP: MPLX term loan facility due 2019 250 250 MPLX bank revolving credit facility due 2020 — 877 MPLX senior notes, 5.500%, due February 2023 710 710 MPLX senior notes, 4.500%, due July 2023 989 989 MPLX senior notes, 4.875%, due December 2024 1,149 1,149 MPLX senior notes, 4.000%, due February 2025 500 500 MPLX senior notes, 4.875%, due June 2025 1,189 1,189 MarkWest senior notes, 4.500% - 5.500%, due 2023 - 2025 63 63 Capital lease obligations due 2016-2028 319 348 Total 11,069 12,475 Unamortized debt issuance costs (44 ) (51 ) Unamortized discount (a) (453 ) (499 ) Amounts due within one year (28 ) (29 ) Total long-term debt due after one year $ 10,544 $ 11,896 (a) Includes $420 million and $464 million discount as of December 31, 2016 and December 31, 2015 , respectively, related to the difference at the time of the acquisition between the fair value and the principal amount of the assumed MarkWest debt.
Schedule Of Debt Payments	The following table shows five years of scheduled debt payments. (In millions) 2017 $ 28 2018 630 2019 477 2020 683 2021 1,031

Supplemental Cash Flow Inform56

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2016
Supplemental Cash Flow Information [Abstract]
Summary of Supplemental Cash Flow Information	(In millions) 2016 2015 2014 Net cash provided by operating activities included: Interest paid (net of amounts capitalized) $ 478 $ 272 $ 166 Net income taxes paid to taxing authorities 140 1,605 1,362 Non-cash investing and financing activities: Capital lease obligations increase $ — $ 1 $ — Contribution of assets to joint venture (a) 272 — — Property, plant and equipment sold — 5 4 Property, plant and equipment acquired — 5 4 Acquisition: Fair value of MPLX units issued (b) — 7,326 — Payable to MPLX Class B unitholders — 50 — (a) Speedway’s contribution of travel plaza locations to new joint venture with Pilot Flying J. (b) See Note 5 .
Schedule Of 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: (In millions) 2016 2015 2014 Additions to property, plant and equipment per consolidated statements of cash flows $ 2,892 $ 1,998 $ 1,480 Non-cash additions to property, plant and equipment — 5 4 Asset retirement expenditures (a) 6 1 2 Increase (decrease) in capital accruals (127 ) 94 95 Total capital expenditures before acquisitions 2,771 2,098 1,581 Acquisitions (b) (133 ) 11,397 2,744 Total capital expenditures $ 2,638 $ 13,495 $ 4,325 (a) Included in All other, net – Operating activities on the consolidated statements of cash flows. (b) 2016 includes adjustments to the fair values of property, plant and equipment, intangibles and goodwill acquired in connection with the MarkWest Merger. The 2015 acquisitions include the MarkWest Merger. The 2014 acquisitions include the acquisition of Hess’ Retail Operations and Related Assets. The acquisition numbers above include property, plant and equipment, intangibles and goodwill. See Note 5 .

Accumulated Other Comprehensi57

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2014 $ (217 ) $ (104 ) $ 4 $ 4 $ (313 ) Other comprehensive income (loss) before reclassifications (44 ) 31 — (1 ) (14 ) Amounts reclassified from accumulated other comprehensive loss: Amortization – prior service credit (a) (46 ) (4 ) — — (50 ) – actuarial loss (a) 51 8 — — 59 – settlement loss (a) 4 — — — 4 Tax effect (3 ) (1 ) — — (4 ) Other comprehensive income (loss) (38 ) 34 — (1 ) (5 ) Balance as of December 31, 2015 $ (255 ) $ (70 ) $ 4 $ 3 $ (318 ) (In millions) Pension Benefits Other Benefits Gain on Cash Flow Hedge Workers Compensation Total Balance as of December 31, 2015 $ (255 ) $ (70 ) $ 4 $ 3 $ (318 ) Other comprehensive income before reclassifications 22 64 — — 86 Amounts reclassified from accumulated other comprehensive loss: Amortization – prior service credit (a) (46 ) (3 ) — — (49 ) – actuarial loss (a) 38 2 — — 40 – settlement loss (a) 7 — — — 7 Other (b) — — — (1 ) (1 ) Tax effect 1 — — — 1 Other comprehensive income (loss) 22 63 — (1 ) 84 Balance as of December 31, 2016 $ (233 ) $ (7 ) $ 4 $ 2 $ (234 ) (a) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 22 . (b) This amount was reclassified out of accumulated other comprehensive loss and is included in selling, general and administrative on the consolidated statements of income.

Defined Benefit Pension and O58

Defined Benefit Pension and Other Postretirement Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Summary Of Defined Benefit Plans With Accumulated Benefit Obligations In Excess Of Plan Assets	The following summarizes our defined benefit pension plans that have accumulated benefit obligations in excess of plan assets. December 31, (In millions) 2016 2015 Projected benefit obligations $ 2,024 $ 1,997 Accumulated benefit obligations 1,914 1,918 Fair value of plan assets 1,659 1,570
Summary Of Projected Benefit Obligations And Funded Status For Defined Benefit Pension And Other Postretirement Plans	The following summarizes the projected benefit obligations and funded status for our defined benefit pension and other postretirement plans: Pension Benefits Other Benefits (In millions) 2016 2015 2016 2015 Change in benefit obligations: Benefit obligations at January 1 $ 1,997 $ 2,075 $ 800 $ 812 Service cost 114 101 32 31 Interest cost 73 71 35 32 Actuarial (gain) loss 15 (63 ) (101 ) (63 ) Benefits paid (175 ) (187 ) (26 ) (24 ) Other (a) — — — 12 Benefit obligations at December 31 2,024 1,997 740 800 Change in plan assets: Fair value of plan assets at January 1 1,570 1,744 — — Actual return on plan assets 145 (33 ) — — Employer contributions 119 46 26 24 Benefits paid from plan assets (175 ) (187 ) (26 ) (24 ) Fair value of plan assets at December 31 1,659 1,570 — — Funded status of plans at December 31 $ (365 ) $ (427 ) $ (740 ) $ (800 ) Amounts recognized in the consolidated balance sheets: Current liabilities $ (18 ) $ (19 ) $ (32 ) $ (29 ) Noncurrent liabilities (347 ) (408 ) (708 ) (771 ) Accrued benefit cost $ (365 ) $ (427 ) $ (740 ) $ (800 ) Pretax amounts recognized in accumulated other comprehensive loss: (b) Net actuarial loss $ 645 $ 723 $ 17 $ 120 Prior service credit (276 ) (323 ) (6 ) (9 ) (a) Includes adjustments related to the MarkWest Merger in 2015. (b) Amounts exclude those related to LOOP and Explorer, equity method investees with defined benefit pension and postretirement plans for which net losses of $16 million and less than $1 million were recorded in accumulated other comprehensive loss in 2016 , reflecting our ownership share.
Components of Net Periodic Benefit Costs	Components of net periodic benefit cost and other comprehensive loss – The following summarizes the net periodic benefit costs and the amounts recognized as other comprehensive loss for our defined benefit pension and other postretirement plans. Pension Benefits Other Benefits (In millions) 2016 2015 2014 2016 2015 2014 Components of net periodic benefit cost: Service cost $ 114 $ 101 $ 88 $ 32 $ 31 $ 27 Interest cost 73 71 74 35 32 33 Expected return on plan assets (98 ) (98 ) (107 ) — — — Amortization – prior service credit (46 ) (46 ) (46 ) (3 ) (4 ) (4 ) – actuarial loss 38 51 51 2 8 2 – settlement loss 7 4 96 — — — Net periodic benefit cost (a) $ 88 $ 83 $ 156 $ 66 $ 67 $ 58 Other changes in plan assets and benefit obligations recognized in other comprehensive loss (pretax): Actuarial (gain) loss $ (33 ) $ 69 $ 188 $ (101 ) $ (63 ) $ 86 Prior service cost (b) — — — — 13 — Amortization of actuarial loss (45 ) (55 ) (147 ) (2 ) (8 ) (2 ) Amortization of prior service cost 46 46 46 3 4 4 Other — — — — — — Total recognized in other comprehensive loss $ (32 ) $ 60 $ 87 $ (100 ) $ (54 ) $ 88 Total recognized in net periodic benefit cost and other comprehensive loss $ 56 $ 143 $ 243 $ (34 ) $ 13 $ 146 (a) Net periodic benefit cost reflects a calculated market-related value of plan assets which recognizes changes in fair value over three years. (b) Includes adjustments related to the MarkWest Merger in 2015.
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Loss (Pretax)	Components of net periodic benefit cost and other comprehensive loss – The following summarizes the net periodic benefit costs and the amounts recognized as other comprehensive loss for our defined benefit pension and other postretirement plans. Pension Benefits Other Benefits (In millions) 2016 2015 2014 2016 2015 2014 Components of net periodic benefit cost: Service cost $ 114 $ 101 $ 88 $ 32 $ 31 $ 27 Interest cost 73 71 74 35 32 33 Expected return on plan assets (98 ) (98 ) (107 ) — — — Amortization – prior service credit (46 ) (46 ) (46 ) (3 ) (4 ) (4 ) – actuarial loss 38 51 51 2 8 2 – settlement loss 7 4 96 — — — Net periodic benefit cost (a) $ 88 $ 83 $ 156 $ 66 $ 67 $ 58 Other changes in plan assets and benefit obligations recognized in other comprehensive loss (pretax): Actuarial (gain) loss $ (33 ) $ 69 $ 188 $ (101 ) $ (63 ) $ 86 Prior service cost (b) — — — — 13 — Amortization of actuarial loss (45 ) (55 ) (147 ) (2 ) (8 ) (2 ) Amortization of prior service cost 46 46 46 3 4 4 Other — — — — — — Total recognized in other comprehensive loss $ (32 ) $ 60 $ 87 $ (100 ) $ (54 ) $ 88 Total recognized in net periodic benefit cost and other comprehensive loss $ 56 $ 143 $ 243 $ (34 ) $ 13 $ 146 (a) Net periodic benefit cost reflects a calculated market-related value of plan assets which recognizes changes in fair value over three years. (b) Includes adjustments related to the MarkWest Merger in 2015.
Plan Assumptions	Plan assumptions – The following summarizes the assumptions used to determine the benefit obligations at December 31, and net periodic benefit cost for the defined benefit pension and other postretirement plans for 2016 , 2015 and 2014 . Pension Benefits Other Benefits 2016 2015 2014 2016 2015 2014 Weighted-average assumptions used to determine benefit obligation: Discount rate 3.90 % 4.00 % 3.65 % 4.25 % 4.50 % 4.15 % Rate of compensation increase 5.00 % 3.70 % 3.70 % 5.00 % 3.70 % 3.70 % Weighted-average assumptions used to determine net periodic benefit cost: Discount rate 3.80 % 3.70 % 4.05 % 4.50 % 4.30 % 4.95 % Expected long-term return on plan assets (a) 6.50 % 6.75 % 7.00 % — % — % — % Rate of compensation increase 5.00 % 3.70 % 3.70 % 5.00 % 3.70 % 3.70 % (a) Effective January 1, 2017, the expected long-term rate of return on plan assets is 6.50 percent due to a continuation of a change in our primary plan investment strategy, which began January 1, 2014.
Assumed Health Care Cost Trend Rates	The following summarizes the assumed health care cost trend rates. December 31, 2016 2015 2014 Health care cost trend rate assumed for the following year: Medical: Pre-65 7.00 % 7.50 % 8.00 % Prescription drugs 9.00 % 7.00 % 7.00 % Rate to which the cost trend rate is assumed to decline (the ultimate trend rate): Medical: Pre-65 4.50 % 5.00 % 5.00 % Prescription drugs 4.50 % 5.00 % 5.00 % Year that the rate reaches the ultimate trend rate: Medical: Pre-65 2026 2021 2021 Prescription drugs 2026 2021 2021
Effects Of One Percentage Point Change In Assumed Health Care Cost Trend Rates	A one percentage point change in assumed health care cost trend rates would have the following effects: 1-Percentage- 1-Percentage- (In millions) Point Increase Point Decrease Effect on total of service and interest cost components $ 6 $ (5 ) Effect on other postretirement benefit obligations 33 (29 )
Fair Values Of Defined Benefit Pension Plan Assets	The following tables present the fair values of our defined benefit pension plans’ assets, by level within the fair value hierarchy, as of December 31, 2016 and 2015 . December 31, 2016 (In millions) Level 1 Level 2 Level 3 Total Cash and cash equivalents $ — $ 24 $ — $ 24 Equity: Common stocks 71 — — 71 Mutual funds 160 — — 160 Pooled funds — 451 — 451 Fixed income: Corporate — 570 — 570 Government — 90 — 90 Pooled funds — 173 — 173 Private equity — — 60 60 Real estate — — 39 39 Other 2 — 19 21 Total investments, at fair value $ 233 $ 1,308 $ 118 $ 1,659 December 31, 2015 (In millions) Level 1 Level 2 Level 3 Total Cash and cash equivalents $ — $ 27 $ — $ 27 Equity: Common stocks 57 — — 57 Mutual funds 142 — — 142 Pooled funds — 399 — 399 Fixed income: Corporate — 516 — 516 Government — 103 — 103 Pooled funds — 193 — 193 Private equity — — 62 62 Real estate — — 50 50 Other 2 — 19 21 Total investments, at fair value $ 201 $ 1,238 $ 131 $ 1,570
Reconciliation Of Beginning And Ending Balances Of Plan Assets Classified As Level 3	The following is a reconciliation of the beginning and ending balances recorded for plan assets classified as Level 3 in the fair value hierarchy: 2016 (In millions) Private Equity Real Estate Other Total Beginning balance $ 62 $ 50 $ 19 $ 131 Actual return on plan assets: Realized 8 5 — 13 Unrealized 2 (3 ) — (1 ) Purchases 2 1 — 3 Sales (14 ) (14 ) — (28 ) Ending balance $ 60 $ 39 $ 19 $ 118 2015 (In millions) Private Equity Real Estate Other Total Beginning balance $ 66 $ 57 $ 21 $ 144 Actual return on plan assets: Realized 12 6 — 18 Unrealized (1 ) (3 ) (2 ) (6 ) Purchases 5 5 — 10 Sales (20 ) (15 ) — (35 ) Ending balance $ 62 $ 50 $ 19 $ 131
Estimated Future Benefit Payment	Estimated future benefit payments – The following gross benefit payments, which reflect expected future service, as appropriate, are expected to be paid in the years indicated. (In millions) Pension Benefits Other Benefits 2017 $ 174 $ 32 2018 177 35 2019 182 37 2020 165 39 2021 165 41 2022 through 2026 801 222
Multi Employer Pension Plan	Our participation in this plan for 2016 , 2015 and 2014 is outlined in the table below. The “EIN” column provides the Employee Identification Number for the plan. The most recent Pension Protection Act zone status available in 2016 and 2015 is for the plan’s year ended December 31, 2015 and December 31, 2014, respectively. The zone status is based on information that we received from the plan and is certified by the plan’s actuary. Among other factors, plans in the red zone are generally less than 65 percent funded. The “FIP/RP Status Pending/Implemented” column indicates a financial improvement plan or a rehabilitation plan has been implemented. The last column lists the expiration date of the collective-bargaining agreement to which the plan is subject. There have been no significant changes that affect the comparability of 2016 , 2015 and 2014 contributions. Our portion of the contributions does not make up more than five percent of total contributions to the plan. Pension Protection Act Zone Status FIP/RP Status Pending/Implemented MPC Contributions In millions ) Surcharge Expiration Date of Collective – Bargaining Pension Fund EIN 2016 2015 2016 2015 2014 Central States, Southeast and Southwest Areas Pension Plan (a) 36-6044243 Red Red Implemented $ 4 $ 4 $ 4 No January 31, 2019 (a) This agreement has a minimum contribution requirement of $303 per week per employee for 2017 . A total of 280 employees participated in the plan as of December 31, 2016 .

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award	The following table reflects activity related to our stock-based compensation arrangements: (In millions) 2016 2015 2014 Stock-based compensation expense $ 45 $ 42 $ 40 Tax benefit recognized on stock-based compensation expense 17 16 15 Cash received by MPC upon exercise of stock option awards 10 33 26 Tax benefit received for tax deductions for stock awards exercised 4 26 19
Weighted Average Assumptions Used To Value Stock Options Awards	The Black Scholes option-pricing model values used to value stock option awards granted were determined based on the following weighted average assumptions: 2016 2015 2014 Weighted average exercise price per share $ 35.27 $ 50.85 $ 42.51 Expected life in years 6.2 6.0 5.8 Expected volatility 38 % 33 % 36 % Expected dividend yield 3.0 % 2.0 % 1.9 % Risk-free interest rate 1.4 % 1.7 % 1.8 % Weighted average grant date fair value of stock option awards granted $ 9.84 $ 13.44 $ 12.69
Summary of Stock Option Award Activity	The following is a summary of our common stock option activity in 2016 : Number of of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Terms (in years) Aggregate Intrinsic Value (in millions) Outstanding at December 31, 2015 8,724,631 $ 27.16 Granted 1,474,177 35.27 Exercised (637,761 ) 18.78 Forfeited, canceled or expired (29,607 ) 42.91 Outstanding at December 31, 2016 9,531,440 28.93 Vested and expected to vest at December 31, 2016 9,518,269 28.90 5.4 $ 205 Exercisable at December 31, 2016 7,094,204 24.90 4.3 181
Summary of Restricted Stock Award Activity	The following is a summary of restricted stock award activity of our common stock in 2016 : Shares of Restricted Stock (“RS”) Restricted Stock Units (“RSU”) Number of Shares Weighted Average Grant Date Fair Value Number of Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2015 1,074,543 $ 47.70 513,220 $ 24.59 Granted 732,074 36.17 45,495 40.85 RS’s Vested/RSU’s Issued (477,339 ) 46.26 (197,598 ) 21.62 Forfeited (78,935 ) 47.53 — — Outstanding at December 31, 2016 1,250,343 41.51 361,117 28.26
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity, Vested And Unvested	The following is a summary of the values related to restricted stock and restricted stock unit awards held by MPC employees and non-employee directors: Restricted Stock Restricted Stock Units Intrinsic Value of Awards Vested During the Period (in millions) Weighted Average Grant Date Fair Value of Awards Granted During the Period Intrinsic Value of Awards Vested During the Period (in millions) Weighted Average Grant Date Fair Value of Awards Granted During the Period 2016 $ 17 $ 36.17 $ 8 $ 40.85 2015 27 50.64 21 49.87 2014 28 43.82 — 42.95
Schedule of Performance Unit Awards	The following table presents a summary of the 2016 activity for performance unit awards to be settled in shares: Number of Units Weighted Average Grant Date Fair Value Outstanding at December 31, 2015 6,145,442 $ 0.92 Granted 2,329,500 0.57 Exercised (1,904,792 ) 0.95 Canceled (314,972 ) 0.93 Outstanding at December 31, 2016 6,255,178 0.78
Schedule of Share-based Compensation, Performance Unit Awards, Valuation Assumptions	Performance units paying out in units have a grant date fair value calculated using a Monte Carlo valuation model, which requires the input of subjective assumptions. The following table provides a summary of these assumptions: 2016 2015 2014 Risk-free interest rate 0.96 % 0.95 % 0.63 % Look-back period 2.83 years 2.84 years 2.84 years Expected volatility 34.15 % 30.38 % 38.51 % Grant date fair value of performance units granted $ 0.57 $ 0.95 $ 0.85

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Schedule Of Future Minimum Commitments	Future minimum commitments as of December 31, 2016 , for capital lease obligations and for operating lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows: (In millions) Capital Lease Obligations Operating Lease Obligations 2017 $ 50 $ 254 2018 50 211 2019 45 198 2020 49 188 2021 45 170 Later years 206 569 Total minimum lease payments 445 $ 1,590 Less imputed interest costs 126 Present value of net minimum lease payments $ 319
Schedule Of Operating Lease Rental Expense	Operating lease rental expense was: (In millions) 2016 2015 2014 Rental expense $ 327 $ 331 $ 256
Schedule of Future Minimum Rental Payments for Operating Leases	The following is a schedule of minimum future rentals on the non‑cancellable operating leases as of December 31, 2016 : (In millions) 2017 $ 197 2018 200 2019 202 2020 201 2021 185 Later years 460 Total minimum lease payments $ 1,445
Schedule of Property Subject to or Available for Operating Lease	The following schedule summarizes our investment in assets held for operating lease by major classes as of December 31, 2016 : (In millions) Natural gas gathering and NGL transportation pipelines and facilities $ 650 Natural gas processing facilities 844 Construction in progress 219 Property, plant and equipment 1,713 Less accumulated depreciation 84 Total property, plant and equipment $ 1,629

Selected Quarterly Financial 61

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Schedule Of Quarterly Financial Information	2016 2015 (In millions, except per share data) 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. 1st Qtr. 2nd Qtr. 3rd Qtr. 4th Qtr. Revenues $ 12,755 $ 16,811 $ 16,618 $ 17,155 $ 17,191 $ 20,537 $ 18,716 $ 15,607 Income from operations 75 1,315 435 553 1,470 1,335 1,549 338 Net income (loss) (78 ) 783 219 289 903 839 958 168 Net income attributable to MPC 1 801 145 227 891 826 948 187 Net income attributable to MPC per share: (a) Basic $ 0.003 $ 1.51 $ 0.28 $ 0.43 $ 1.63 $ 1.52 $ 1.77 $ 0.35 Diluted 0.003 1.51 0.27 0.43 1.62 1.51 1.76 0.35 Dividends paid per share 0.32 0.32 0.36 0.36 0.25 0.25 0.32 0.32 (a) We completed a two-for-one stock split in June 2015. All historical per share data has been retroactively restated on a post-split basis.

Supplementary Statistics (Table

Supplementary Statistics (Tables)	12 Months Ended
	Dec. 31, 2016
Text Block [Abstract]
Supplementary Statistics	(In millions) 2016 2015 2014 Income from Operations by segment Refining & Marketing (a) $ 1,543 $ 4,086 $ 3,538 Speedway (a) 734 673 544 Midstream (b) 871 380 342 Items not allocated to segments: Corporate and other unallocated items (b) (277 ) (299 ) (277 ) Pension settlement expenses (7 ) (4 ) (96 ) Impairment (c) (486 ) (144 ) — Income from operations $ 2,378 $ 4,692 $ 4,051 Capital Expenditures and Investments (d)(e) Refining & Marketing $ 1,101 $ 1,045 $ 1,043 Speedway 303 501 2,981 Midstream 1,521 14,545 604 Corporate and Other (f) 144 192 110 Total $ 3,069 $ 16,283 $ 4,738 (a) In 2016, the Refining & Marketing and Speedway segments include an inventory LCM benefit of $345 million and $25 million , respectively. In 2015, the Refining & Marketing and Speedway segments include an inventory LCM charge of $345 million and $25 million , respectively. (b) Included in the Midstream segment for 2016 , 2015 and 2014 are $11 million , $20 million and $19 million of corporate overhead expenses attributable to MPLX. The remaining corporate overhead expenses are not currently allocated to other segments, but instead reported in corporate and other unallocated items. (c) 2016 relates to impairments of goodwill and equity method investments. 2015 relates to the cancellation of the Residual Oil Upgrader Expansion project. See Notes 15 , 16 and 17 to the audited consolidated financial statements. (d) Capital expenditures include changes in capital accruals. (e) Includes $13.85 billion in 2015 for the MarkWest Merger and $2.71 billion in 2014 for the acquisition of Hess’ Retail Operations and Related Assets. See Note 5 . (f) Includes capitalized interest of $63 million , $37 million and $27 million for 2016 , 2015 and 2014 , respectively.
Operating Statistics	2016 2015 2014 MPC Consolidated Refined Product Sales Volumes (mbpd) (a) 2,269 2,301 2,138 Refining & Marketing Operating Statistics Refining & Marketing refined product sales volume (mbpd) (b) 2,259 2,289 2,125 Refining & Marketing gross margin (dollars per barrel) (c)(d) $ 11.26 $ 15.25 $ 15.05 Crude oil capacity utilization percent (e) 95 99 95 Refinery throughputs (mbpd): (f) Crude oil refined 1,699 1,711 1,622 Other charge and blendstocks 151 177 184 Total 1,850 1,888 1,806 Sour crude oil throughput percent 60 55 52 WTI-priced crude oil throughput percent 19 20 19 Refined product yields (mbpd): (f) Gasoline 900 913 869 Distillates 617 603 580 Propane 35 36 35 Feedstocks and special products 241 281 276 Heavy fuel oil 32 31 25 Asphalt 58 55 54 Total 1,883 1,919 1,839 Refinery direct operating costs (dollars per barrel): (g) Planned turnaround and major maintenance $ 1.83 $ 1.13 $ 1.80 Depreciation and amortization 1.47 1.39 1.41 Other manufacturing (h) 4.09 4.15 4.86 Total $ 7.39 $ 6.67 $ 8.07 Refining & Marketing Operating Statistics By Region – Gulf Coast Refinery throughputs (mbpd): (i) Crude oil refined 1,039 1,060 991 Other charge and blendstocks 195 184 182 Total 1,234 1,244 1,173 Sour crude oil throughput percent 73 68 64 WTI-priced crude oil throughput percent 8 6 3 Refined product yields (mbpd): (i) Gasoline 514 534 508 Distillates 399 392 368 Propane 26 26 23 Feedstocks and special products 286 286 274 Heavy fuel oil 21 15 13 Asphalt 15 16 13 Total 1,261 1,269 1,199 Refinery direct operating costs (dollars per barrel): (g) Planned turnaround and major maintenance $ 2.09 $ 0.81 $ 1.82 Depreciation and amortization 1.14 1.09 1.15 Other manufacturing (h) 3.70 3.88 4.73 Total $ 6.93 $ 5.78 $ 7.70 Supplementary Statistics (Unaudited) 2016 2015 2014 Refining & Marketing Operating Statistics By Region – Midwest Refinery throughputs (mbpd): (i) Crude oil refined 660 651 631 Other charge and blendstocks 39 39 45 Total 699 690 676 Sour crude oil throughput percent 40 34 33 WTI-priced crude oil throughput percent 38 43 44 Refined product yields (mbpd): (i) Gasoline 386 379 361 Distillates 218 211 212 Propane 11 12 13 Feedstocks and special products 35 38 43 Heavy fuel oil 12 17 13 Asphalt 43 39 41 Total 705 696 683 Refinery direct operating costs (dollars per barrel): (g) Planned turnaround and major maintenance $ 1.15 $ 1.64 $ 1.66 Depreciation and amortization 1.88 1.83 1.78 Other manufacturing (h) 4.29 4.36 4.76 Total $ 7.32 $ 7.83 $ 8.20 Speedway Operating Statistics (j) Convenience stores at period-end (k) 2,733 2,766 2,746 Gasoline and distillate sales (millions of gallons) 6,094 6,038 3,942 Gasoline & distillate gross margin (dollars per gallon) (d)(l) $ 0.1656 $ 0.1823 $ 0.1775 Merchandise sales (in millions) $ 5,007 $ 4,879 $ 3,611 Merchandise gross margin (in millions) $ 1,435 $ 1,368 $ 975 Merchandise gross margin percent 28.7 % 28.0 % 27.0 % Same store gasoline sales volume (period over period) (0.4 )% (0.3 )% (0.7 )% Same store merchandise sales (period over period) (m) 3.2 % 4.1 % 5.0 % Midstream Operating Statistics Crude oil and refined product pipeline throughputs (mbpd) (n) 2,311 2,191 2,119 Gathering system throughput (MMcf/d) (o) 3,275 3,075 Natural gas processed (MMcf/d) (o) 5,761 5,468 C2 (ethane) + NGLs (natural gas liquids) fractionated (mbpd) (o) 335 307 (a) Total average daily volumes of refined product sales to wholesale, branded and retail customers. (b) Includes intersegment sales. (c) Sales revenue less cost of refinery inputs and purchased products, divided by total refinery throughputs. (d) Excludes the lower of cost or market adjustment. (e) Based on calendar day capacity, which is an annual average that includes downtime for planned maintenance and other normal operating activities. (f) Excludes inter-refinery volumes of 83 mbpd, 46 mbpd and 43 mbpd for 2016 , 2015 and 2014 , respectively. (g) Per barrel of total refinery throughputs. (h) Includes utilities, labor, routine maintenance and other operating costs. (i) Includes inter-refinery transfer volumes. (j) Includes the impact of Hess’ Retail Operations and Related Assets from the September 30, 2014 acquisition date. (k) Decrease in 2016 was primarily due to the contribution of 41 travel centers to the Pilot joint venture. (l) The price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, divided by gasoline and distillate sales volume. (m) Excludes cigarettes. (n) On owned common-carrier pipelines, excluding equity method investments. (o) Includes the results of the MarkWest assets beginning on the Dec. 4, 2015 acquisition date.Includes amounts related to unconsolidated equity method investments on a 100% basis.

Summary Of Principal Accounti63

Summary Of Principal Accounting Policies (Details) $ in Millions	Dec. 04, 2015	Dec. 31, 2016USD ($)Company	Dec. 31, 2015USD ($)
Summary Of Principal Accounting Policies [Line Items]
Restricted cash and cash equivalents | $		$ 5	$ 9
Accounts receivable number of days past-due evaluated for doubtful accounts		180 days
Stock Options
Summary Of Principal Accounting Policies [Line Items]
Implied volatility rate weighting (in percentage)		50.00%
Historical volatility rate weighting (in percentage)		50.00%
Minimum
Summary Of Principal Accounting Policies [Line Items]
Number of companies engaged in crude oil or refinery feedstock trading agreement | Company		100
Estimated useful lives (in years)		2 years
Maximum
Summary Of Principal Accounting Policies [Line Items]
Estimated useful lives (in years)		42 years
Accounts Receivable with Master Netting Arrangements | Customer Concentration Risk
Summary Of Principal Accounting Policies [Line Items]
Percentage of accounts receivable related to sales of crude oil refinery feed stocks to customers with master netting agreements		23.00%	26.00%
MPLX LP
Summary Of Principal Accounting Policies [Line Items]
MPC's ownership percentage of the general partner interest		100.00%
Noncontrolling interest (in percentage)		74.50%
MPLX LP | General Partner and Limited Partner
Summary Of Principal Accounting Policies [Line Items]
MPC's partnership interest in MPLX (in percentage)		25.50%
MPLX LP | General Partner
Summary Of Principal Accounting Policies [Line Items]
MPC's partnership interest in MPLX (in percentage)		2.00%
MarkWest | MPLX LP
Summary Of Principal Accounting Policies [Line Items]
Common units conversion ratio	1.09

MPLX LP (Narrative) (Detail)

MPLX LP (Narrative) (Detail) - MPLX LP	Dec. 04, 2015	Dec. 31, 2016BargeTow_Boat
Noncontrolling Interest [Line Items]
Number of tow boats | Tow_Boat		18
Number of barges | Barge		200
MPC's ownership percentage of the general partner interest		100.00%
Noncontrolling interest (in percentage)		74.50%
MarkWest
Noncontrolling Interest [Line Items]
Common units conversion ratio	1.09
Butane Cavern
Noncontrolling Interest [Line Items]
Ownership interest (in percentage)		100.00%
General Partner
Noncontrolling Interest [Line Items]
MPC's partnership interest in MPLX (in percentage)		2.00%
General Partner and Limited Partner
Noncontrolling Interest [Line Items]
MPC's partnership interest in MPLX (in percentage)		25.50%
MPLX Pipe Line Holdings LP
Noncontrolling Interest [Line Items]
Ownership interest (in percentage)	100.00%	100.00%

MPLX LP (Reorganization Transac

MPLX LP (Reorganization Transactions) (Details) - MPLX LP - USD ($) shares in Millions, $ in Millions	Sep. 01, 2016	Mar. 31, 2016	Dec. 01, 2014
Noncontrolling Interest [Line Items]
General partners' contributed capital	$ 225
Limited Partner
Noncontrolling Interest [Line Items]
Units issued, number of units	7	23	2.9
General Partner and Limited Partner
Noncontrolling Interest [Line Items]
Increase in ownership percentage by MPC	1.00%

MPLX LP (Private Placement of P

MPLX LP (Private Placement of Preferred Units) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	May 13, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Issuance of MPLX LP redeemable preferred units		$ 984	$ 0	$ 0
Series A Convertible Preferred Units | MPLX LP
Noncontrolling Interest [Line Items]
Preferred units, dividend rate, percentage	6.50%
Issuance of MPLX LP redeemable preferred units	$ 984
Preferred units, dividend rate, per-dollar-amount	$ 0.528125
Preferred units, description	The MPLX Preferred Units are convertible into MPLX common units on a one for one basis after three years, at the purchasers’ option, and after four years at MPLX’s option, subject to certain conditions.
Series A Convertible Preferred Units | Preferred Units | MPLX LP
Noncontrolling Interest [Line Items]
Sale of units (number of units)	30.8
Units issued, price per share	$ 32.50

MPLX LP (Dropdowns to MPLX) (De

MPLX LP (Dropdowns to MPLX) (Details) - USD ($) shares in Thousands, $ in Millions	Sep. 01, 2016	Mar. 31, 2016	Dec. 04, 2015	Dec. 01, 2014	Mar. 01, 2014	Dec. 31, 2016
MPLX LP | Limited Partner
Noncontrolling Interest [Line Items]
Units issued, number of units	7,000	23,000		2,900
Equity interest issued, value assigned		$ 600		$ 200
MPLX LP | General Partner
Noncontrolling Interest [Line Items]
Units issued, number of units		460
MPLX LP | MPLX Revolver
Noncontrolling Interest [Line Items]
Cash payment for acquisition				$ 600	$ 270
MPLX LP | Cash and cash equivalents
Noncontrolling Interest [Line Items]
Cash payment for acquisition					$ 40
MPLX Pipe Line Holdings LP
Noncontrolling Interest [Line Items]
Additional interest sold			0.50%	30.50%	13.00%
Proceeds from sale of ownership interest in assets sold by company in affiliate			$ 12	$ 600	$ 310
MPLX Pipe Line Holdings LP | MPLX LP
Noncontrolling Interest [Line Items]
Ownership interest (in percentage)			100.00%			100.00%

MPLX LP (Public Offerings) (Det

MPLX LP (Public Offerings) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Feb. 12, 2015	Dec. 08, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 22, 2015	Dec. 14, 2015
Noncontrolling Interest [Line Items]
Issuance of MPLX LP common units			$ 776	$ 0	$ 221
Senior Notes
Noncontrolling Interest [Line Items]
Debt instrument, face amount							$ 1,500
MPLX LP
Noncontrolling Interest [Line Items]
Issuance of MPLX LP common units		$ 221
MPLX LP | Senior Notes
Noncontrolling Interest [Line Items]
Debt instrument, face amount						$ 4,040
MPLX LP | Senior Notes | MPLX senior notes, 4.000%, due February 2025
Noncontrolling Interest [Line Items]
Debt instrument, face amount	$ 500
Debt instrument, interest rate	4.00%		4.00%
Debt instrument, maturity date	Feb. 15, 2025		Feb. 15, 2025
MPLX LP | Limited Partner
Noncontrolling Interest [Line Items]
Public offering of common units (in number of common units)		3.5
Units issued, price per share		$ 66.68

MPLX LP (ATM Program) (Details)

MPLX LP (ATM Program) (Details) - USD ($) shares in Millions, $ in Millions	Dec. 08, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Issuance of MPLX LP common units		$ 776	$ 0	$ 221
MPLX LP
Noncontrolling Interest [Line Items]
Issuance of MPLX LP common units	$ 221
MPLX LP | ATM Program
Noncontrolling Interest [Line Items]
Issuance of MPLX LP common units		776
Remaining authorized issuance amount		$ 717
MPLX LP | ATM Program | Limited Partners Common Units
Noncontrolling Interest [Line Items]
Sale of units (number of units)		26

MPLX LP (Noncontrolling Interes

MPLX LP (Noncontrolling Interest) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Impact from equity transactions of MPLX	$ 658	$ 6,923	$ 221
Additional Paid-in Capital
Increase (decrease) in MPC's paid in capital for the issuance of MPLX LP common units to the public	(60)	1,532
Increase in MPC's paid in capital for the issuance of MPLX LP common units and general partner units to MPC	121	0
Net transfers (to) from noncontrolling interests	61	1,532
Tax impact	(118)	(404)
Impact from equity transactions of MPLX	$ (57)	$ 1,128

Acquisitions and Investments (M

Acquisitions and Investments (Merger with MarkWest Energy Partners, L.P.) (Details) $ / shares in Units, $ in Millions		Dec. 04, 2015USD ($)reporting_unit$ / shares	Jul. 31, 2017USD ($)	Jul. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)reporting_unit	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Business Acquisition [Line Items]
Payable to seller							$ 50
Goodwill, purchase price accounting adjustments						$ (241)
Goodwill					$ 4,019	$ 3,587	4,019	$ 1,566
Number of reporting units | reporting_unit						3
Midstream
Business Acquisition [Line Items]
Goodwill, purchase price accounting adjustments	[1]					$ (241)
Goodwill					2,627	2,256	2,627	$ 173
MPLX LP
Business Acquisition [Line Items]
Goodwill					2,570	$ 2,199	$ 2,570
MarkWest
Business Acquisition [Line Items]
Cash consideration to unitholders (per unit) | $ / shares		$ 6.20
Cash payment to MarkWest unitholders		$ 1,230			$ 1,280
Payable to seller		50		$ 25
Equity method investments		2,600
Property, plant and equipment, net		8,517
Goodwill		$ 2,213
Number of reporting units | reporting_unit		3
Transaction costs		$ 6
MarkWest | Selling, General and Administrative Expenses
Business Acquisition [Line Items]
Transaction costs		30
MarkWest | Net Interest and Other Financial Income
Business Acquisition [Line Items]
Transaction costs		6
MarkWest | Midstream
Business Acquisition [Line Items]
Transaction costs		36
MarkWest | Misstatement of Original Purchase Price Allocation [Member]
Business Acquisition [Line Items]
Goodwill, purchase price accounting adjustments		(68)
Equity method investments		2
Property, plant and equipment, net		2
MarkWest | Customer contracts and relationships
Business Acquisition [Line Items]
Intangibles		468
MarkWest | Customer contracts and relationships | Misstatement of Original Purchase Price Allocation [Member]
Business Acquisition [Line Items]
Intangibles		$ 64
MarkWest | Customer contracts and relationships | Minimum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life (in years)		11 years
MarkWest | Customer contracts and relationships | Maximum
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life (in years)		25 years
MarkWest | Scenario, Forecast
Business Acquisition [Line Items]
Payable to seller			$ 25
MarkWest | MPLX LP
Business Acquisition [Line Items]
Common units conversion ratio		1.09
[1]	See Note 5 for information on the acquisitions and purchase price allocation adjustments.

Acquisitions and Investments (F

Acquisitions and Investments (Fair Value of Consideration Transferred - MarkWest) (Details) - USD ($) $ in Millions	Dec. 04, 2015	Jul. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Business Acquisition [Line Items]
Fair value of MPLX units issued				$ 0	$ 7,326	[1]	$ 0
Payable to seller					$ 50
MarkWest
Business Acquisition [Line Items]
Fair value of MPLX units issued	$ 7,326
Cash payment to MarkWest unitholders	1,230		$ 1,280
Payable to seller	50	$ 25
Total fair value of consideration transferred	$ 8,606
[1]	See Note 5.

Acquisitions and Investments (S

Acquisitions and Investments (Schedule of Assets Acquired and Liabilities Assumed - MarkWest) (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015	Dec. 04, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill		$ 3,587	$ 4,019		$ 1,566
MarkWest
Business Acquisition [Line Items]
Cash and cash equivalents				$ 12
Receivables				164
Inventories				32
Other current assets				44
Equity method investments				2,600
Property, plant and equipment, net				8,517
Other noncurrent assets				538
Total assets acquired				11,907
Accounts payable				328
Payroll and benefits payable				13
Accrued taxes				21
Other current liabilities				44
Long-term debt				4,567
Deferred income taxes				377
Deferred credits and other liabilities				151
Noncontrolling interests				13
Total liabilities and noncontrolling interest assumed				5,514
Net assets acquired excluding goodwill				6,393
Goodwill				2,213
Net assets acquired				8,606
MarkWest | Scenario, Previously Reported
Business Acquisition [Line Items]
Cash and cash equivalents				12
Receivables				164
Inventories				33
Other current assets				44
Equity method investments				2,457
Property, plant and equipment, net				8,474
Other noncurrent assets				473
Total assets acquired				11,657
Accounts payable				322
Payroll and benefits payable				13
Accrued taxes				21
Other current liabilities				44
Long-term debt				4,567
Deferred income taxes				374
Deferred credits and other liabilities				151
Noncontrolling interests				13
Total liabilities and noncontrolling interest assumed				5,505
Net assets acquired excluding goodwill				6,152
Goodwill				2,454
Net assets acquired				8,606
MarkWest | Scenario, Adjustment
Business Acquisition [Line Items]
Cash and cash equivalents				0
Receivables				0
Inventories				(1)
Other current assets				0
Equity method investments				143
Property, plant and equipment, net				43
Other noncurrent assets	[1]			65
Total assets acquired				250
Accounts payable				6
Payroll and benefits payable				0
Accrued taxes				0
Other current liabilities				0
Long-term debt				0
Deferred income taxes				3
Deferred credits and other liabilities				0
Noncontrolling interests				0
Total liabilities and noncontrolling interest assumed				9
Net assets acquired excluding goodwill				241
Goodwill				(241)
Net assets acquired				$ 0
[1]	The adjustment relates to acquired intangible assets.

Acquisitions and Investments (R

Acquisitions and Investments (Revenues and Earnings of MarkWest Included in Consolidated Statements of Income) (Details) - MarkWest $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Sales and other operating revenues (including consumer excise taxes)	$ 120
Income from operations	$ 32

Acquisitions and Investments (A

Acquisitions and Investments (Acquisition of Hess' Retail Operations and Related Assets) (Details) bbl / d in Thousands, $ in Millions	Sep. 30, 2014USD ($)bbl / d	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Business Acquisition [Line Items]
Goodwill		$ 3,587	$ 4,019	$ 1,566
Hess Retail Operations and Related Assets
Business Acquisition [Line Items]
Allocation of space on Colonial Pipeline (in barrels per day) | bbl / d	40
Cash payment for acquisition	$ 2,820
Net working capital adjustment	(3)
Goodwill	629
Transaction costs	$ 14

Acquisitions and Investments 76

Acquisitions and Investments (Revenues and Earnings of Hess Retail Included in Consolidated Statement of Income) (Details) - Hess Retail Operations and Related Assets $ in Millions	12 Months Ended
	Dec. 31, 2014USD ($)
Business Acquisition [Line Items]
Sales and other operating revenues (including consumer excise taxes)	$ 2,403
Income from operations	$ 113

Acquisitions and Investments 77

Acquisitions and Investments (Schedule of Acquisition Related Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Business Combinations [Abstract]
Sales and other operating revenues (including consumer excise taxes)	$ 73,760	$ 108,605
Net income attributable to MPC	$ 2,825	$ 2,522
Net income attributable to MPC per share – basic	$ 5.25	$ 4.42
Net income attributable to MPC per share – diluted	$ 5.21	$ 4.39

Acquisitions and Investments 78

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

Acquisitions and Investments 79

Acquisitions and Investments (Formation of Travel Plaza Joint Venture) (Details) $ in Millions		12 Months Ended
		Dec. 31, 2016USD ($)Store		Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Schedule of Equity Method Investments [Line Items]
Contribution of fixed assets to joint venture		$ 272	[1]	$ 0	$ 0
PFJ Southeast
Schedule of Equity Method Investments [Line Items]
Convenience stores | Store		123
Contribution of fixed assets to joint venture	[1]	$ 272
PFJ Southeast | Property, Plant and Equipment
Schedule of Equity Method Investments [Line Items]
Contribution of fixed assets to joint venture	[1]	203
PFJ Southeast | Goodwill
Schedule of Equity Method Investments [Line Items]
Contribution of fixed assets to joint venture	[1]	61
PFJ Southeast | Inventories
Schedule of Equity Method Investments [Line Items]
Contribution of fixed assets to joint venture	[1]	$ 8
PFJ Southeast | Speedway
Schedule of Equity Method Investments [Line Items]
Convenience stores | Store		41
PFJ Southeast | Pilot Flying J
Schedule of Equity Method Investments [Line Items]
Convenience stores | Store		82
[1]	Speedway’s contribution of travel plaza locations to new joint venture with Pilot Flying J.

Acquisitions and Investments 80

Acquisitions and Investments (Marine Investments) (Details) $ in Millions	1 Months Ended	12 Months Ended		16 Months Ended
	May 31, 2016USD ($)	Dec. 31, 2016Joint_venturevessel	Dec. 31, 2015vessel	Dec. 31, 2016USD ($)Joint_venturevessel	Sep. 30, 2015
Crowley Coastal Partners
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage	50.00%	50.00%		50.00%
Cash paid to acquire equity method investments | $	$ 48			$ 189
Crowley Ocean Partners
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage	50.00%	50.00%		50.00%	50.00%
Number of vessels | vessel		2	2	4
Cash paid to acquire equity method investments | $				$ 141
Crowley Blue Water Partners
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		50.00%		50.00%
Number of vessels | vessel		3
Crowley Maritime Corporation
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | Joint_venture		2		2

Acquisitions and Investments (I

Acquisitions and Investments (Investments in Pipeline Companies) (Details) bbl / d in Thousands, $ in Millions	Feb. 15, 2017USD ($)bbl / d	Mar. 04, 2014USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Jan. 01, 2019
Explorer
Schedule of Equity Method Investments [Line Items]
Cash paid to acquire equity method investments		$ 77
Equity method investments, ownership percentage		25.00%	25.00%		25.00%
Ownership percentage acquired		7.00%
Illinois Extension Pipeline
Schedule of Equity Method Investments [Line Items]
Cash paid to acquire equity method investments				$ 299
Equity method investments, ownership percentage			35.00%		35.00%
North Dakota Pipeline
Schedule of Equity Method Investments [Line Items]
Cash paid to acquire equity method investments			$ 14		$ 301
Equity method investments, ownership percentage			37.50%		37.50%
North Dakota Pipeline Class A Units | Scenario, Forecast
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage						27.00%
Subsequent Event | MarEn Bakken Company LLC | MPLX LP
Schedule of Equity Method Investments [Line Items]
Cash paid to acquire equity method investments	$ 500
Equity method investments, ownership percentage	25.00%
Subsequent Event | MarEn Bakken Company LLC | MPLX & Enbridge Energy Partners
Schedule of Equity Method Investments [Line Items]
Cash paid to acquire equity method investments	$ 2,000
Subsequent Event | Bakken Pipeline System
Schedule of Equity Method Investments [Line Items]
Crude oil throughput | bbl / d	470
Subsequent Event | Bakken Pipeline System | MPLX LP
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage	9.20%
Subsequent Event | Bakken Pipeline System | MPLX & Enbridge Energy Partners
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest in joint venture acquired	36.75%

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Millions	Dec. 31, 2016	May 31, 2016
Crowley Coastal Partners
Schedule of Equity Method Investments [Line Items]
Maximum loss exposure, amount	$ 489
Equity method investments, ownership percentage	50.00%	50.00%
MarkWest Utica EMG
Schedule of Equity Method Investments [Line Items]
Maximum loss exposure, amount	$ 2,220
Equity method investments, ownership percentage	56.00%
Ohio Gathering
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage	34.00%

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	May 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Mar. 04, 2014
Related Party Transaction [Line Items]
Long-term receivable from related party	$ 1		$ 1
Centennial
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	50.00%
Crowley Blue Water Partners
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	50.00%
Crowley Ocean Partners
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	50.00%	50.00%		50.00%
Explorer
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	25.00%				25.00%
Illinois Extension Pipeline
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	35.00%
LOCAP
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	59.00%
LOOP
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	51.00%
MarkWest Utica EMG
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	56.00%
Ohio Condensate
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	60.00%
Ohio Gathering
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	34.00%
PFJ Southeast
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	29.00%
TAAE
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	45.00%
TACE
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	61.00%
TAME
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	67.00%

Related Party Transactions (Sal

Related Party Transactions (Sales to Related Parties) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Revenue from Related Parties	$ 62	$ 6	$ 7
PFJ Southeast
Related Party Transaction [Line Items]
Revenue from Related Parties	56	0	0
Other equity method investees
Related Party Transaction [Line Items]
Revenue from Related Parties	$ 6	$ 6	$ 7

Related Party Transactions (Oth

Related Party Transactions (Other Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Other income from related parties	$ 41	$ 4	$ 1
MarkWest Utica EMG
Related Party Transaction [Line Items]
Other income from related parties	16	0	0
Ohio Condensate
Related Party Transaction [Line Items]
Other income from related parties	4	0	0
Ohio Gathering
Related Party Transaction [Line Items]
Other income from related parties	15	2	0
Other equity method investees
Related Party Transaction [Line Items]
Other income from related parties	$ 6	$ 2	$ 1

Related Party Transactions (Pur

Related Party Transactions (Purchases From Related Parties) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Purchases from related parties	$ 509	$ 308	$ 505
Crowley Blue Water Partners
Related Party Transaction [Line Items]
Purchases from related parties	37	0	0
Crowley Ocean Partners
Related Party Transaction [Line Items]
Purchases from related parties	52	6	0
Explorer
Related Party Transaction [Line Items]
Purchases from related parties	14	20	39
Illinois Extension Pipeline
Related Party Transaction [Line Items]
Purchases from related parties	110	4	0
LOCAP
Related Party Transaction [Line Items]
Purchases from related parties	23	23	21
LOOP
Related Party Transaction [Line Items]
Purchases from related parties	59	52	88
TAAE
Related Party Transaction [Line Items]
Purchases from related parties	41	52	79
TACE
Related Party Transaction [Line Items]
Purchases from related parties	59	54	121
TAME
Related Party Transaction [Line Items]
Purchases from related parties	93	87	141
Other equity method investees
Related Party Transaction [Line Items]
Purchases from related parties	$ 21	$ 10	$ 16

Related Party Transactions (Rec

Related Party Transactions (Receivables From Related Parties) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Current receivables from related parties	$ 45	$ 13
Centennial
Related Party Transaction [Line Items]
Current receivables from related parties	0	1
MarkWest Utica EMG
Related Party Transaction [Line Items]
Current receivables from related parties	2	1
Ohio Condensate
Related Party Transaction [Line Items]
Current receivables from related parties	0	3
Ohio Gathering
Related Party Transaction [Line Items]
Current receivables from related parties	2	5
PFJ Southeast
Related Party Transaction [Line Items]
Current receivables from related parties	40	0
Other equity method investees
Related Party Transaction [Line Items]
Current receivables from related parties	$ 1	$ 3

Related Party Transactions (Pay

Related Party Transactions (Payables To Related Parties) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Payables to related parties	$ 53	$ 42
Explorer
Related Party Transaction [Line Items]
Payables to related parties	0	1
Illinois Extension Pipeline
Related Party Transaction [Line Items]
Payables to related parties	9	4
LOCAP
Related Party Transaction [Line Items]
Payables to related parties	2	2
LOOP
Related Party Transaction [Line Items]
Payables to related parties	6	5
MarkWest Utica EMG
Related Party Transaction [Line Items]
Payables to related parties	24	19
Ohio Condensate
Related Party Transaction [Line Items]
Payables to related parties	1	4
TAAE
Related Party Transaction [Line Items]
Payables to related parties	2	1
TACE
Related Party Transaction [Line Items]
Payables to related parties	4	2
TAME
Related Party Transaction [Line Items]
Payables to related parties	4	3
Other equity method investees
Related Party Transaction [Line Items]
Payables to related parties	$ 1	$ 1

Income per Common Share (Summar

Income per Common Share (Summary Of Earnings Per Common Share) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic earnings per share:
Net income attributable to MPC	$ 227	$ 145	$ 801	$ 1	$ 187	$ 948	$ 826	$ 891		$ 1,174	$ 2,852	$ 2,524
Income allocated to participating securities, basic										1	4	4
Income available to common stockholders – basic										$ 1,173	$ 2,848	$ 2,520
Weighted average common shares outstanding (in shares)										528	538	570
Basic (in USD per share)	$ 0.43	$ 0.28	$ 1.51	$ 0.003	$ 0.35	$ 1.77	$ 1.52	$ 1.63	[1]	$ 2.22	$ 5.29	$ 4.42
Diluted earnings per share:
Net income attributable to MPC	$ 227	$ 145	$ 801	$ 1	$ 187	$ 948	$ 826	$ 891		$ 1,174	$ 2,852	$ 2,524
Income allocated to participating securities, diluted										1	4	4
Income available to common stockholders – diluted										$ 1,173	$ 2,848	$ 2,520
Weighted average common shares outstanding (in shares)										528	538	570
Effect of dilutive securities (in shares)										2	4	4
Weighted average common shares, including dilutive effect (in shares)										530	542	574
Diluted (in USD per share)	$ 0.43	$ 0.27	$ 1.51	$ 0.003	$ 0.35	$ 1.76	$ 1.51	$ 1.62	[1]	$ 2.21	$ 5.26	$ 4.39
[1]	We completed a two-for-one stock split in June 2015. All historical per share data has been retroactively restated on a post-split basis.

Income Per Common Share (Anti-d

Income Per Common Share (Anti-dilutive Shares) (Detail) - shares shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Shares issued under stock-based compensation plans
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	3	1	1

Equity (Narrative) (Detail)

Equity (Narrative) (Detail) $ in Millions	Dec. 31, 2016USD ($)
Equity [Abstract]
Stock repurchase plan remaining authorized amount	$ 2,560

Equity (Share Repurchases) (Det

Equity (Share Repurchases) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Number of shares repurchased	4	19	49
Cash paid for shares repurchased	$ 197	$ 965	$ 2,131
Effective average cost per delivered share	$ 41.84	$ 50.31	$ 44.31

Segment Information (Narrative)

Segment Information (Narrative) (Detail) - Segment	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Number of reportable segments	3
None | Maximum
Segment Reporting Information [Line Items]
Percent of annual revenues	10.00%	10.00%	10.00%

Segment Information (Income Fro

Segment Information (Income From Operations Attributable To Operating Segments) (Detail) - USD ($) $ in Millions		Dec. 04, 2015	Sep. 30, 2014	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												$ 63,339		$ 72,051		$ 97,817
Income from operations				$ 553	$ 435	$ 1,315	$ 75	$ 338	$ 1,549	$ 1,335	$ 1,470	2,378		4,692		4,051
Income from equity method investments												(185)		88		153
Depreciation and amortization												2,001		1,502		1,326
Segment capital expenditures and investments												3,069		16,283		4,738
Inventory market valuation adjustment												(370)		370		0
MarkWest
Segment Reporting Information [Line Items]
Transaction costs		$ 6
Hess Retail Operations and Related Assets
Segment Reporting Information [Line Items]
Segment capital expenditures and investments																2,710
Transaction costs			$ 14
Refining & Marketing
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												43,228		52,174		80,821
Inventory market valuation adjustment	[1]											(345)		345
Speedway
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												18,283		19,690		16,927
Inventory market valuation adjustment	[1]											(25)		25
Midstream
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												1,828		187		71
Midstream | MarkWest
Segment Reporting Information [Line Items]
Transaction costs		36
Reportable Segment
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												63,339		72,051		97,819
Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												11,400		12,804		11,670
Intersegment Eliminations | Refining & Marketing
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	[2]											10,589		12,024		10,912
Intersegment Eliminations | Speedway
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	[2]											3		3		5
Intersegment Eliminations | Midstream
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	[2]											808		777		753
Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												74,739		84,855		109,489
Income from operations												3,148		5,139		4,424
Income from equity method investments												171	[3]	88		153
Depreciation and amortization	[3]											1,941		1,450		1,274
Segment capital expenditures and investments												2,925		16,091		4,628
Operating Segments | Refining & Marketing
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												53,817		64,198		91,733
Income from operations												1,543	[4]	4,086	[4]	3,538
Income from equity method investments												24		26		96
Depreciation and amortization												1,092		1,052		1,020
Segment capital expenditures and investments	[5]											1,101		1,045		1,043	[6]
Operating Segments | Refining & Marketing | Hess Retail Operations and Related Assets
Segment Reporting Information [Line Items]
Segment capital expenditures and investments			52
Operating Segments | Speedway
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												18,286		19,693		16,932
Income from operations												734	[4]	673	[4]	544
Income from equity method investments												5		0		0
Depreciation and amortization												273		254		152
Segment capital expenditures and investments	[5]											303		501		2,981	[6]
Operating Segments | Speedway | Hess Retail Operations and Related Assets
Segment Reporting Information [Line Items]
Segment capital expenditures and investments			$ 2,660
Operating Segments | Midstream
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)												2,636		964		824
Income from operations	[7]											871		380		342
Income from equity method investments												142		62		57
Depreciation and amortization												576		144		102
Segment capital expenditures and investments	[5]											1,521		14,545	[8]	604
Operating Segments | Midstream | MarkWest
Segment Reporting Information [Line Items]
Segment capital expenditures and investments		$ 13,850
Operating Segments | Midstream | MPLX LP
Segment Reporting Information [Line Items]
Cost of services, overhead												$ 11		$ 20		$ 19
[1]	2016 includes impairments of goodwill and equity method investments. 2015 relates to the cancellation of the ROUX project at our Garyville refinery. See Notes 15, 16 and 17.
[2]	Management believes intersegment transactions were conducted under terms comparable to those with unaffiliated parties.
[3]	Differences between segment totals and MPC totals represent amounts related to unallocated items and are included in “Items not allocated to segments” in the reconciliation below.
[4]	he Refining & Marketing and Speedway segments include an inventory LCM charge of $345 million and $25 million, respectively.
[5]	Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.
[6]	The Speedway and Refining & Marketing segments include $2.66 billion and $52 million, respectively, for the acquisition of Hess’ Retail Operations and Related Assets. See Note 5.
[7]	Included in the Midstream segment for 2016, 2015 and 2014 are $11 million, $20 million and $19 million, respectively, of corporate overhead expenses attributable to MPLX. The remaining corporate overhead expenses are not currently allocated to other segments, but instead are reported in corporate and other unallocated items. Also included in the Midstream segment for 2015 are $36 million of transaction costs related to the MarkWest Merger.
[8]	The Midstream segment includes $13.85 billion for the MarkWest Merger. See Note 5.

Segment Information (Reconcilia

Segment Information (Reconciliation Of Segment Income From Operations To Income Before Income Taxes) (Detail) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income from operations		$ 553	$ 435	$ 1,315	$ 75	$ 338	$ 1,549	$ 1,335	$ 1,470	$ 2,378		$ 4,692		$ 4,051
Net interest and other financial income (costs)										556		318		216
Income before income taxes										1,822		4,374		3,835
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income from operations										3,148		5,139		4,424
Corporate and Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income from operations	[1]									(277)		(299)		(277)
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pension settlement expenses	[2]									(7)		(4)		(96)
Impairment										$ (486)	[3]	$ (144)	[3]	$ 0
[1]	Included in the Midstream segment for 2016, 2015 and 2014 are $11 million, $20 million and $19 million of corporate overhead expenses attributable to MPLX. The remaining corporate overhead expenses are not currently allocated to other segments, but instead reported in corporate and other unallocated items.
[2]	See Note 22.
[3]	2016 includes impairments of goodwill and equity method investments. 2015 relates to the cancellation of the ROUX project at our Garyville refinery. See Notes 15, 16 and 17.

Segment Information (Reconcil96

Segment Information (Reconciliation Of Segment Capital Expenditures And Investments To Total Capital Expenditures) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Segment Reporting, Other Significant Reconciling Item [Line Items]
Segment capital expenditures and investments		$ 3,069	$ 16,283		$ 4,738
Plus items not allocated to segments:
Total capital expenditures	[1]	2,638	13,495		4,325
Scenario, Adjustment | MarkWest
Segment Reporting, Other Significant Reconciling Item [Line Items]
Cash paid to acquire equity method investments		143
Scenario, Previously Reported | MarkWest
Segment Reporting, Other Significant Reconciling Item [Line Items]
Cash paid to acquire equity method investments			2,460
Operating Segments
Segment Reporting, Other Significant Reconciling Item [Line Items]
Segment capital expenditures and investments		2,925	16,091		4,628
Cash paid to acquire equity method investments		431	2,788	[2]	413
Corporate and Other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Segment capital expenditures and investments	[3],[4]	144	192		110
Plus items not allocated to segments:
Corporate and Other		81	155		83
Capitalized interest		$ 63	$ 37		$ 27
[1]	Capital expenditures include changes in capital accruals. See Note 20 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.
[2]	2016 includes an adjustment of $143 million to the fair value of equity method investments acquired in connection with the MarkWest Merger. 2015 includes $2.46 billion for the MarkWest Merger. See Note 5
[3]	Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.
[4]	Includes capitalized interest of $63 million, $37 million and $27 million for 2016, 2015 and 2014, respectively.

Segment Information (Reconcil97

Segment Information (Reconciliation Of Total Segment Customer Revenues To Sales And Other Operating Revenues) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting, Revenue Reconciling Item [Line Items]
Sales and other operating revenues (including consumer excise taxes)	$ 63,339	$ 72,051	$ 97,817
Corporate and Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Sales and other operating revenues (including consumer excise taxes)	0	0	(2)
Reportable Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Sales and other operating revenues (including consumer excise taxes)	$ 63,339	$ 72,051	$ 97,819

Segment Information (Schedule O

Segment Information (Schedule Of Revenues By Product Line) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	$ 63,339	$ 72,051	$ 97,817
Refined products
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	54,511	63,744	90,702
Merchandise
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	5,297	5,188	3,817
Crude oil and refinery feedstocks
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	2,038	2,718	2,917
Service, transportation and other
Segment Reporting Information [Line Items]
Sales and other operating revenues (including consumer excise taxes)	$ 1,493	$ 401	$ 381

Segment Information (Total Asse

Segment Information (Total Assets By Reportable Segment) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	$ 44,413	$ 43,115
Operating Segments | Refining & Marketing
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	18,039	17,379
Operating Segments | Speedway
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	5,426	5,349
Operating Segments | Midstream
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	18,078	17,462
Corporate and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	$ 2,870	$ 2,925

Other Items (Net Interest And O

Other Items (Net Interest And Other Financial Income (Costs)) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014	Dec. 04, 2015
Interest income	$ 6		$ 6		$ 7
Interest expense	(602)	[1]	(325)	[1]	(229)
Interest capitalized	64		37		27
Loss on extinguishment of debt	0		(5)		0
Other financial costs	(24)		(31)	[2]	(21)
Net interest and other financial income (costs)	(556)		(318)		$ (216)
MarkWest
Transaction costs						$ 6
MarkWest | MPLX LP | Senior Notes
Amortization of debt discount	$ 44		$ 1
[1]	2016 and 2015 includes $44 million and $1 million, respectively, for the amortization of the discount related to the difference between the fair value and the principal amount of the assumed MarkWest debt
[2]	2015 includes $6 million of transaction costs related to the MarkWest Merger.

Income Taxes (Components Of Inc

Income Taxes (Components Of Income Tax Provisions (Benefits)) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current
Federal	$ 189	$ 1,210	$ 1,382
State and local	27	152	135
Foreign	(1)	10	5
Total	215	1,372	1,522
Deferred
Federal	336	134	(199)
State and local	57	9	(37)
Foreign	1	(9)	(6)
Total	394	134	(242)
Total
Federal	525	1,344	1,183
State and local	84	161	98
Foreign	0	1	(1)
Total	$ 609	$ 1,506	$ 1,280

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Statutory rate applied to income before income taxes	35.00%	35.00%	35.00%
Tax effect of issuance of MPLX LP units - MarkWest Merger	$ 115
Unrecognized tax benefits that would impact effective income tax rate	2
Uncertain tax positions, reasonably possible increase or decrease during the next twelve months	1
Unrecognized tax benefits income tax net penalties and interest expense (benefits)	(5)	$ 3	$ 1
Interest and penalties accrued	$ 13	$ 18

Income Taxes (Reconciliation Of

Income Taxes (Reconciliation Of Federal Statutory Income Tax Rate) (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Statutory rate applied to income before income taxes	35.00%	35.00%	35.00%
State and local income taxes, net of federal income tax effects	3.00%	2.00%	2.00%
Domestic manufacturing deduction	(1.00%)	(2.00%)	(2.00%)
Noncontrolling interests	(1.00%)	(0.00%)	(0.00%)
Biodiesel excise tax credit	(1.00%)	(1.00%)	(0.00%)
Other	(2.00%)	0.00%	(2.00%)
Provision for income taxes	33.00%	34.00%	33.00%

Income Taxes (Components Of Def

Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Employee benefits	$ 578	$ 631
Environmental	34	44
Net operating loss carryforwards	23	73
Other	58	73
Total deferred tax assets	693	821
Deferred tax liabilities:
Property, plant and equipment	2,591	2,512
Inventories	707	579
Investments in subsidiaries and affiliates	1,145	909
Other	94	89
Total deferred tax liabilities	4,537	4,089
Net deferred tax liabilities	$ 3,844	$ 3,268

Income Taxes (Components Of Net

Income Taxes (Components Of Net Deferred Tax Liabilities Classified In Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets
Other noncurrent assets	$ 17	$ 17
Liabilities
Deferred income taxes	3,861	3,285
Net deferred tax liabilities	$ 3,844	$ 3,268

Income Taxes (Tax Carryforwards

Income Taxes (Tax Carryforwards) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 04, 2015
United States Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 18	$ 66
United States Federal | Minimum
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration date	Jan. 1, 2022
United States Federal | Maximum
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration date	Dec. 31, 2036
States
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 8		$ 10
States | Minimum
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration date	Jan. 1, 2017
States | Maximum
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration date	Dec. 31, 2036

Income Taxes (Valuation Allowan

Income Taxes (Valuation Allowances) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Valuation allowance	$ 10	$ 5

Income Taxes (Summary Of Income

Income Taxes (Summary Of Income Tax Returns Subject To Examination) (Detail)	12 Months Ended
	Dec. 31, 2016
United States Federal | Minimum
Income Tax Examination [Line Items]
Tax years	2,010
United States Federal | Maximum
Income Tax Examination [Line Items]
Tax years	2,015
States | Minimum
Income Tax Examination [Line Items]
Tax years	2,008
States | Maximum
Income Tax Examination [Line Items]
Tax years	2,015

Income Taxes (Summary Of Activi

Income Taxes (Summary Of Activity In Unrecognized Tax Benefits) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
January 1 balance	$ 12	$ 12	$ 13
Additions for tax positions of prior years	6	0	7
Reductions for tax positions of prior years	(10)	0	(10)
Settlements, decrease	(1)
Settlements, increase		0	2
December 31 balance	$ 7	$ 12	$ 12

Inventories (Summary Of Invento

Inventories (Summary Of Inventories) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Crude oil and refinery feedstocks	$ 2,208	$ 2,180
Refined products	2,810	2,804
Materials and supplies	485	438
Merchandise	153	173
Lower of cost or market reserve	0	(370)
Total	$ 5,656	$ 5,225

Inventories (Narrative) (Detail

Inventories (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Total inventory LIFO percentage	91.00%		91.00%	91.00%
Lower of cost or market reserve	$ 0		$ 0	$ 370
Inventory market valuation adjustment			370	(370)	$ 0
Excess of current acquisition costs over stated LIFO value	308		308
Effect of LIFO inventory liquidation on income	$ 54	$ (54)	$ 0	$ (78)	$ 0

Equity Method Investments (Sche

Equity Method Investments (Schedule Of Equity Method Investments) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		May 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Mar. 04, 2014
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 3,827			$ 3,622
MPLX LP
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 2,467			2,458
Centennial
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		50.00%
Equity method investments		$ 35			37
Centrahoma Processing LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		40.00%
Equity method investments		$ 104			111
Crowley Coastal Partners
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		50.00%		50.00%
Equity method investments		$ 184			0
Crowley Ocean Partners
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		50.00%		50.00%		50.00%
Equity method investments		$ 0	[1]		72
Explorer
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		25.00%					25.00%
Equity method investments		$ 94			91
Illinois Extension Pipeline
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		35.00%
Equity method investments		$ 293			267
LOCAP
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		59.00%
Equity method investments		$ 22			22
LOOP
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		51.00%
Equity method investments		$ 277			243
MarkWest Utica EMG
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		56.00%
Equity method investments		$ 2,224			2,160
North Dakota Pipeline
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments from asset impairment		$ (267)
Equity method investments, ownership percentage		37.50%
Equity method investments		$ 30	[2]		287
Ohio Condensate
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments from asset impairment		$ (89)
Equity method investments, ownership percentage		60.00%
Equity method investments		$ 10	[2]		101
PFJ Southeast
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		29.00%
Equity method investments		$ 283	[3]		0
TAAE
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		45.00%
Equity method investments		$ 33			27
TACE
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		61.00%
Equity method investments		$ 33			49
TAEI
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		34.00%
Equity method investments		$ 15			18
TAME
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		67.00%
TAME | Direct Ownership Interest
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership percentage		50.00%
Equity method investments	[4]	$ 18			27
Other equity method investees
Schedule of Equity Method Investments [Line Items]
Equity method investments		43			24
Other equity method investees | MPLX LP
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 129			$ 86
[1]	Crowley Ocean Partners merged into Crowley Coastal Partners in 2016.
[2]	During 2016, we recorded an impairment charge of $267 million related to our investment in North Dakota Pipeline and an impairment charge of $89 million related to our investment in Ohio Condensate. See Note 17 for additional information.
[3]	This joint venture with Pilot Flying J was formed in 2016. See Note 5.
[4]	Excludes TAEI’s investment in TAME.

Equity Method Investments (Summ

Equity Method Investments (Summarized Financial Information For Equity Method Investees) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income statement data:
Revenues and other income	$ 2,421	$ 1,390	$ 1,430
Income (loss) from operations	(116)	332	379
Net income (loss)	(250)	239	$ 316
Balance sheet data – December 31:
Current assets	711	906
Noncurrent assets	8,170	6,418
Current liabilities	884	468
Noncurrent liabilities	$ 1,462	$ 1,130

Equity Method Investments (Narr

Equity Method Investments (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Equity method investment difference between carrying amount and underlying equity	$ 1,210
Equity method investment difference between carrying amount and underlying equity, portion related to goodwill which is not being amortized	553
Equity method investments	3,827	$ 3,622
Dividends and partnership distributions received from equity method investees	291	113	$ 170
Centennial
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 35	$ 37
Percent of debt outstanding	50.00%
Centennial | Financial Guarantee
Schedule of Equity Method Investments [Line Items]
Maximum potential undiscounted payments	$ 29

Property, Plant And Equipmen115

Property, Plant And Equipment (Summary Of Property, Plant And Equipment) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 38,006	$ 35,604
Less accumulated depreciation	12,241	10,440
Net property, plant and equipment	25,765	25,164
Operating Segments | Refining & Marketing
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	19,447	18,396
Operating Segments | Speedway
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,078	5,067
Operating Segments | Midstream
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	12,664	11,379
Corporate and Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 817	$ 762
Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	2 years
Minimum | Operating Segments | Refining & Marketing
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	2 years
Minimum | Operating Segments | Speedway
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	4 years
Minimum | Operating Segments | Midstream
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	3 years
Minimum | Corporate and Other
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	4 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	42 years
Maximum | Operating Segments | Refining & Marketing
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	30 years
Maximum | Operating Segments | Speedway
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	25 years
Maximum | Operating Segments | Midstream
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	42 years
Maximum | Corporate and Other
Property, Plant and Equipment [Line Items]
Estimated useful lives (in years)	40 years

Property, Plant And Equipmen116

Property, Plant And Equipment (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 35,604	$ 38,006
Property, plant and equipment, accumulated depreciation	10,440	12,241
Residual Oil Upgrader Expansion project - Garyville [Member]
Property, Plant and Equipment [Line Items]
Impairment charge	144
Assets held under capital leases
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	511	505
Property, plant and equipment, accumulated depreciation	176	202
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,260	$ 2,020

Goodwill (Narrative) (Detail)

Goodwill (Narrative) (Detail) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)reporting_unit	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Goodwill [Line Items]
Number of reporting units | reporting_unit			3
Impairment expense			$ 130	$ 0
Number of reporting units impaired | reporting_unit			2
Fair Value, Measurements, Nonrecurring
Goodwill [Line Items]
Impairment expense			$ 130	$ 0	$ 0
Midstream
Goodwill [Line Items]
Impairment expense	$ 1	$ 129	$ 130
Midstream | Fair Value, Measurements, Nonrecurring | Goodwill | Minimum
Goodwill [Line Items]
Discount rate			10.50%
Midstream | Fair Value, Measurements, Nonrecurring | Goodwill | Maximum
Goodwill [Line Items]
Discount rate			11.50%

Goodwill (Changes In Carrying A

Goodwill (Changes In Carrying Amount Of Goodwill) (Detail) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
		Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2016		Dec. 31, 2015
Goodwill [Line Items]
Beginning balance			$ 4,019	$ 4,019		$ 1,566
Goodwill, acquisitions						2,454
Goodwill, purchase price accounting adjustments				(241)
Goodwill, disposition				(61)		(1)
Goodwill, impairment				(130)		0
Ending balance		$ 3,587		3,587		4,019
Refining & Marketing
Goodwill [Line Items]
Beginning balance			539	539		539
Goodwill, acquisitions						0
Goodwill, purchase price accounting adjustments				0
Goodwill, disposition				0		0
Goodwill, impairment				0
Ending balance		539		539		539
Speedway
Goodwill [Line Items]
Beginning balance			853	853		854
Goodwill, acquisitions						0
Goodwill, purchase price accounting adjustments				0
Goodwill, disposition				(61)	[1]	(1)
Goodwill, impairment				0
Ending balance		792		792		853
Midstream
Goodwill [Line Items]
Beginning balance			2,627	2,627		173
Goodwill, acquisitions	[2]					2,454
Goodwill, purchase price accounting adjustments	[2]			(241)
Goodwill, disposition				0		0
Goodwill, impairment		(1)	$ (129)	(130)
Ending balance		$ 2,256		$ 2,256		$ 2,627
[1]	Goodwill associated with our former Speedway travel plaza locations that are now part of the PFJ Southeast joint venture. The amount was included in the initial basis for our equity method investment in the joint venture.
[2]	See Note 5 for information on the acquisitions and purchase price allocation adjustments.

Intangibles (Intangible Assets

Intangibles (Intangible Assets by Major Class) (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		$ 924	$ 856
Accumulated amortization		(199)	(137)
Net		725	719
Customer contracts and relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		636	560
Royalty agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		128	122
Favorable lease contract terms
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		58	71
Other intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		102	103
Refining & Marketing
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		258	242
Accumulated amortization		(123)	(104)
Net		135	138
Indefinite-lived intangible assets		3	3
Refining & Marketing | Customer contracts and relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		102	91
Refining & Marketing | Royalty agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		128	122
Refining & Marketing | Favorable lease contract terms
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		1	1
Refining & Marketing | Other intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	[1]	27	28
Speedway
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		133	146
Accumulated amortization		(35)	(31)
Net		98	115
Indefinite-lived intangible assets		46	46
Speedway | Customer contracts and relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		1	1
Speedway | Royalty agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		0	0
Speedway | Favorable lease contract terms
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		57	70
Speedway | Other intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	[1]	75	75
Midstream
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		533	468
Accumulated amortization		(41)	(2)
Net		492	466
Midstream | Customer contracts and relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		533	468
Midstream | Royalty agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		0	0
Midstream | Favorable lease contract terms
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		0	0
Midstream | Other intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross		$ 0	$ 0
[1]	Refining & Marketing and Speedway segments include unamortized intangible assets of $3 million and $46 million, respectively

Intangibles (Narrative) (Detail

Intangibles (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 50	$ 29

Intangibles (Estimated Future A

Intangibles (Estimated Future Amortization Expense) (Details) $ in Millions	Dec. 31, 2016USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,017	$ 49
2,018	49
2,018	49
2,019	48
2,020	$ 46

Fair Value Measurements (Assets

Fair Value Measurements (Assets And Liabilities Accounted For At Fair Value On Recurring Basis) (Detail) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash collateral netted with derivative liabilities		$ 24
Cash collateral netted with derivative assets			$ (23)
Contingent consideration, current		130	196
Embedded derivative in commodity contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Embedded derivative instruments, current		13	5
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - collateral and netting		(688)	(62)
Commodity derivative instruments, assets - collateral pledged not offset		126	0
Other assets		2	2
Total assets at fair value		2	53
Commodity derivative instruments, liabilities - netting and collateral		(712)	(39)
Commodity derivative instruments, liabilities - collateral pledged not offset		0	0
Contingent consideration, liability	[1]	130	317
Total liabilities at fair value		190	349
Fair Value, Measurements, Recurring | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets		2	2
Total assets at fair value		690	106
Contingent consideration, liability		0	0
Total liabilities at fair value		712	39
Fair Value, Measurements, Recurring | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets		0	0
Total assets at fair value		0	2
Contingent consideration, liability		0	0
Total liabilities at fair value		0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other assets		0	0
Total assets at fair value		0	7
Contingent consideration, liability		130	317
Total liabilities at fair value		190	349
Fair Value, Measurements, Recurring | Commodity derivative instruments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - collateral and netting	[2]	(688)	(62)
Commodity derivative instruments, assets - net	[3]	0	51
Commodity derivative instruments, assets - collateral pledged not offset		126	0
Commodity derivative instruments, liabilities - netting and collateral	[2]	(712)	(39)
Commodity derivative instruments, liabilities, net	[3]	6	0
Commodity derivative instruments, liabilities - collateral pledged not offset		0	0
Fair Value, Measurements, Recurring | Commodity derivative instruments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		688	104
Commodity derivative instruments, liabilities - gross		712	39
Fair Value, Measurements, Recurring | Commodity derivative instruments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		0	2
Commodity derivative instruments, liabilities - gross		0	0
Fair Value, Measurements, Recurring | Commodity derivative instruments | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, assets - gross		0	7
Commodity derivative instruments, liabilities - gross		6	0
Fair Value, Measurements, Recurring | Embedded derivative in commodity contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, liabilities - netting and collateral	[2]	0	0
Commodity derivative instruments, liabilities, net	[3],[4]	54	32
Commodity derivative instruments, liabilities - collateral pledged not offset		0	0
Fair Value, Measurements, Recurring | Embedded derivative in commodity contracts | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, liabilities - gross		0	0
Fair Value, Measurements, Recurring | Embedded derivative in commodity contracts | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, liabilities - gross		0	0
Fair Value, Measurements, Recurring | Embedded derivative in commodity contracts | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivative instruments, liabilities - gross		$ 54	$ 32
[1]	Includes $130 million and $196 million classified as current as of December 31, 2016 and 2015, respectively.
[2]	Represents the impact of netting assets, liabilities and cash collateral when a legal right of offset exists. As of December 31, 2016, cash collateral of $24 million was netted with mark-to-market derivative liabilities. As of December 31, 2015, cash collateral of $23 million was netted with mark-to-market derivative assets.
[3]	We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet.
[4]	Includes $13 million and $5 million classified as current as of December 31, 2016 and 2015, respectively.

Fair Value Measurements (Recurr

Fair Value Measurements (Recurring Narrative) (Detail)	12 Months Ended		30 Months Ended
	Dec. 31, 2016USD ($)$ / bbl	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Feb. 01, 2013USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees	$ 899,000,000	$ 1,600,000,000
Galveston Bay Refinery and Related Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maximum earnout payment, year four				$ 250,000,000
Maximum earnout payment, year five				250,000,000
Maximum earnout payment, year six				250,000,000
Maximum earnout provision payable to the company				$ 700,000,000
Cash payment for acquisition			$ 569,000,000
Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees	$ 131,000,000	$ 331,000,000	131,000,000
Fair Value, Measurements, Recurring | Galveston Bay Refinery and Related Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range of internal and external crack spread forecast per barrel | $ / bbl	13
Fair Value, Measurements, Recurring | Minimum | Galveston Bay Refinery and Related Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	5.00%
Fair Value, Measurements, Recurring | Maximum | Galveston Bay Refinery and Related Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	10.00%
Embedded derivative 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 derivative instruments | Ethanol prices | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward commodity price	$ 0.28		0.28
Level 3 | Commodity derivative instruments | Ethanol prices | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forward commodity price	$ 1.27		$ 1.27
Level 3 | Embedded derivative in commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of renewal	50.00%
Probability of renewal second term	75.00%

Fair Value Measurements (Reconc

Fair Value Measurements (Reconciliation Of Net Beginning And Ending Balances Recorded For Net Assets And Liabilities Classified As Level 3) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance		$ 342	$ 478	$ 625
Contingent consideration payment	[1]	(200)	(189)	(180)
Net derivative positions assumed - MarkWest Merger		0	31	0
Unrealized and realized losses included in net income		55	20	33
Settlements of derivative instruments		(7)	2	0
Ending balance		190	342	478
Contingent consideration payment		$ 164	$ 175	$ 172
[1]	On the consolidated statements of cash flows for 2016, 2015 and 2014, $164 million, $175 million and $172 million, respectively, of the contingent earnout payment to BP was included as a financing activity with the remainder included as an operating activity.

Fair Value Measurements (Gains_

Fair Value Measurements (Gains/Losses Included In Earnings Relating to Assets Still Held at the End of Period) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in unrealized gain (loss)	$ 45	$ 21	$ 33
Derivative
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in unrealized gain (loss)	32	(7)	0
Contingent Consideration
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in unrealized gain (loss)	$ 13	$ 28	$ 33

Fair Value Measurements (Ass126

Fair Value Measurements (Assets Measured At Fair Value On Nonrecurring Basis) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, impairment	$ 130	$ 0
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investments, fair value	42	0	$ 0
Equity method investment, impairment	356	0	0
Goodwill, fair value	0	0	0
Goodwill, impairment	130	0	0
Property, plant and equipment, net, fair value	0	0	0
Property, plant and equipment, net, impairment	0	144	0
Other noncurrent assets, fair value	0	0	0
Other noncurrent assets, impairment	$ 0	$ 0	$ 11

Fair Value Measurements (Nonrec

Fair Value Measurements (Nonrecurring Narrative) (Details) - USD ($) $ in Millions	12 Months Ended			38 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
North Dakota Pipeline
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investments, ownership percentage	37.50%			37.50%
Income (loss) from equity method investments	$ (267)
Cash paid to acquire equity method investments	$ 14			$ 301
Ohio Condensate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investments, ownership percentage	60.00%			60.00%
Income (loss) from equity method investments	$ (89)
Ohio Condensate | Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	11.20%
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investment, impairment	$ 356	$ 0	$ 0
Impairment charge	0	144	0
Other noncurrent assets, impairment	0	$ 0	$ 11
Fair Value, Measurements, Nonrecurring | North Dakota Pipeline
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Income (loss) from equity method investments	(267)
Fair Value, Measurements, Nonrecurring | Ohio Condensate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Income (loss) from equity method investments	(58)
Equity method investment, impairment	96
Income (loss) from equity method investments from elimination of basis differential	$ (31)

Fair Value Measurements (Financ

Fair Value Measurements (Financial Instruments At Fair Value, Excluding Derivative Financial Instruments) (Detail) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Fair Value
Financial assets:
Investments		$ 25	$ 33
Other		21	35
Total financial assets		46	68
Financial liabilities:
Long-term debt	[1]	10,892	11,366
Deferred credits and other liabilities		121	136
Total financial liabilities		11,013	11,502
Carrying Value
Financial assets:
Investments		2	2
Other		21	33
Total financial assets		23	35
Financial liabilities:
Long-term debt	[1]	10,297	11,628
Deferred credits and other liabilities		109	135
Total financial liabilities		$ 10,406	$ 11,763
[1]	Excludes capital leases and debt issuance costs, however, includes amount classified as debt due within one year.

Derivatives (Classification Of

Derivatives (Classification Of Gross Fair Values Of Derivative Instruments, Excluding Cash Collateral) (Detail) - Commodity derivative instruments - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Other current assets
Derivatives, Fair Value [Line Items]
Asset		$ 688	$ 113
Liability		712	39
Other current liabilities(a)
Derivatives, Fair Value [Line Items]
Asset		0	0
Liability	[1]	13	5
Deferred credits and other liabilities
Derivatives, Fair Value [Line Items]
Asset		0	0
Liability	[1]	$ 47	$ 27
[1]	Includes embedded derivatives.

Derivatives (Open Commodity Der

Derivatives (Open Commodity Derivative Contracts - Crude Oil) (Detail) - Crude Oil bbl in Thousands	12 Months Ended
	Dec. 31, 2016bbl
Exchange Traded
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	98.70%
Derivative contract expiration date	Mar. 31, 2017
Exchange Traded | Long
Derivative [Line Items]
Notional contracts (in thousands of total barrels)	53,028	[1]
Exchange Traded | Short
Derivative [Line Items]
Notional contracts (in thousands of total barrels)	52,373	[1]
Over the Counter | Short
Derivative [Line Items]
Notional contracts (in thousands of total barrels)	37
[1]	of the exchange-traded contracts expire in the first quarter of 2017.

Derivatives (Open Commodity 131

Derivatives (Open Commodity Derivative Contracts - Natural Gas) (Details)	Dec. 31, 2016MMBTU
Over the Counter | Long
Derivative [Line Items]
Notional contracts (in MMbtu)	297,017

Derivatives (Open Commodity 132

Derivatives (Open Commodity Derivative Contracts - Refined Product) (Details) - Refined products gal in Thousands	12 Months Ended
	Dec. 31, 2016gal
Exchange Traded
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	100.00%
Derivative contract expiration date	Mar. 31, 2017
Exchange Traded | Long
Derivative [Line Items]
Notional contracts (in thousands of total gallons)	196,434	[1]
Exchange Traded | Short
Derivative [Line Items]
Notional contracts (in thousands of total gallons)	221,970	[1]
Over the Counter | Short
Derivative [Line Items]
Notional contracts (in thousands of total gallons)	64,212
[1]	of the exchange-traded contracts expire in the first quarter of 2017.

Derivatives (Effect Of Commodit

Derivatives (Effect Of Commodity Derivative Instruments In Statements Of Income) (Detail) - Commodity derivative instruments - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	$ (180)	$ 313	$ 493
Sales and other operating revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	(13)	19	37
Cost of revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	$ (167)	$ 294	$ 456

Debt (Outstanding Borrowings) (

Debt (Outstanding Borrowings) (Detail) - USD ($) $ in Millions		Jul. 20, 2016	Oct. 27, 2015	Feb. 12, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 22, 2015
Debt Instrument [Line Items]
Commercial paper					$ 0	$ 0
Total					11,069	12,475
Unamortized debt issuance costs					(44)	(51)
Unamortized discount	[1]				(453)	(499)
Amounts due within one year					(28)	(29)
Total long-term debt due after one year					10,544	11,896
MPLX LP
Debt Instrument [Line Items]
Amounts due within one year					(1)	(1)
Total long-term debt due after one year					4,422	5,255
Senior Notes | MPLX LP | MarkWest
Debt Instrument [Line Items]
Long-term debt, gross					63	63
Unamortized discount					(420)	(464)
Capital Lease Obligations [Member] | Consolidated subsidiaries:
Debt Instrument [Line Items]
Capital lease obligations					$ 319	348
Debt instrument maturity year, start					Jan. 1, 2016
Debt instrument maturity year, end					Dec. 31, 2028
364-day bank revolving credit facility due July 2017
Debt Instrument [Line Items]
Line of credit facility, expiration date		Jul. 19, 2017
364-day bank revolving credit facility due July 2017 | Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross					$ 0	0
Line of credit facility, expiration date					Jul. 19, 2017
Trade receivables securitization facility due July 2019
Debt Instrument [Line Items]
Line of credit facility, expiration date		Jul. 19, 2019
Trade receivables securitization facility due July 2019 | Secured Debt
Debt Instrument [Line Items]
Long-term debt, gross					$ 0	0
Line of credit facility, expiration date					Jul. 19, 2019
Bank revolving credit facility due 2020
Debt Instrument [Line Items]
Line of credit facility, expiration date		Jul. 20, 2020
Bank revolving credit facility due 2020 | Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross					$ 0	0
Line of credit facility, expiration date					Jul. 20, 2020
Term loan agreement due 2019 | Unsecured Debt
Debt Instrument [Line Items]
Long-term debt, gross					$ 200	700
Line of credit facility, expiration date					Sep. 30, 2019
Senior notes, 2.700% due December 2018 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross					$ 600	600
Debt instrument, maturity date					Dec. 14, 2018
Debt instrument, interest rate					2.70%
Senior notes, 3.400% due December 2020 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross					$ 650	650
Debt instrument, maturity date					Dec. 15, 2020
Debt instrument, interest rate					3.40%
Senior notes, 5.125% due March 2021 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross					$ 1,000	1,000
Debt instrument, maturity date					Mar. 1, 2021
Debt instrument, interest rate					5.125%
Senior notes, 3.625%, due September 2024 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross					$ 750	750
Debt instrument, maturity date					Sep. 15, 2024
Debt instrument, interest rate					3.625%
Senior notes, 6.500%, due March 2041 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross					$ 1,250	1,250
Debt instrument, maturity date					Mar. 1, 2041
Debt instrument, interest rate					6.50%
Senior notes, 4.750%, due September 2044 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross					$ 800	800
Debt instrument, maturity date					Sep. 15, 2044
Debt instrument, interest rate					4.75%
Senior notes, 5.850% due December 2045 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross					$ 250	250
Debt instrument, maturity date					Dec. 15, 2045
Debt instrument, interest rate					5.85%
Senior notes, 5.000%, due September 2054 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross					$ 400	400
Debt instrument, maturity date					Sep. 15, 2054
Debt instrument, interest rate					5.00%
MPLX term loan facility due 2019 | Unsecured Debt | MPLX LP
Debt Instrument [Line Items]
Long-term debt, gross					$ 250	250
Line of credit facility, expiration date			Nov. 20, 2019		Nov. 20, 2019
MPLX bank revolving credit facility due 2020 | Line of Credit | MPLX LP
Debt Instrument [Line Items]
Long-term debt, gross					$ 0	877
Line of credit facility, expiration date			Dec. 4, 2020		Dec. 4, 2020
MPLX senior notes, 5.500%, due February 2023 | Senior Notes | MPLX LP
Debt Instrument [Line Items]
Long-term debt, gross					$ 710	710	$ 710
Debt instrument, maturity date					Feb. 15, 2023
Debt instrument, interest rate					5.50%		5.50%
MPLX senior notes, 5.500%, due February 2023 | Senior Notes | MPLX LP | MarkWest
Debt Instrument [Line Items]
Long-term debt, gross							$ 40
Debt instrument, maturity date					Feb. 15, 2023
Debt instrument, interest rate					5.50%		5.50%
MPLX senior notes, 4.500%, due July 2023 | Senior Notes | MPLX LP
Debt Instrument [Line Items]
Long-term debt, gross					$ 989	989	$ 989
Debt instrument, maturity date					Jul. 15, 2023
Debt instrument, interest rate					4.50%		4.50%
MPLX senior notes, 4.500%, due July 2023 | Senior Notes | MPLX LP | MarkWest
Debt Instrument [Line Items]
Long-term debt, gross							$ 11
Debt instrument, maturity date					Jul. 15, 2023
Debt instrument, interest rate					4.50%		4.50%
MPLX senior notes, 4.875%, due December 2024 | Senior Notes | MPLX LP
Debt Instrument [Line Items]
Long-term debt, gross					$ 1,149	1,149	$ 1,150
Debt instrument, maturity date					Dec. 1, 2024
Debt instrument, interest rate					4.875%		4.875%
MPLX senior notes, 4.875%, due December 2024 | Senior Notes | MPLX LP | MarkWest
Debt Instrument [Line Items]
Long-term debt, gross							$ 1
Debt instrument, maturity date					Dec. 1, 2024
Debt instrument, interest rate					4.875%		4.875%
MPLX senior notes, 4.000%, due February 2025 | Senior Notes | MPLX LP
Debt Instrument [Line Items]
Long-term debt, gross					$ 500	500
Debt instrument, maturity date				Feb. 15, 2025	Feb. 15, 2025
Debt instrument, interest rate				4.00%	4.00%
MPLX senior notes, 4.875%, due June 2025 | Senior Notes | MPLX LP
Debt Instrument [Line Items]
Long-term debt, gross					$ 1,189	$ 1,189	$ 1,190
Debt instrument, maturity date					Jun. 1, 2025
Debt instrument, interest rate					4.875%		4.875%
MPLX senior notes, 4.875%, due June 2025 | Senior Notes | MPLX LP | MarkWest
Debt Instrument [Line Items]
Long-term debt, gross							$ 11
Debt instrument, maturity date					Jun. 1, 2025
Debt instrument, interest rate					4.875%		4.875%
[1]	Includes $420 million and $464 million discount as of December 31, 2016 and December 31, 2015, respectively, related to the difference at the time of the acquisition between the fair value and the principal amount of the assumed MarkWest debt.

Debt (Schedule Of Debt Payments

Debt (Schedule Of Debt Payments) (Detail) $ in Millions	Dec. 31, 2016USD ($)
Debt Disclosure [Abstract]
2,017	$ 28
2,018	630
2,019	477
2,019	683
2,020	$ 1,031

Debt (Commercial Paper) (Detail

Debt (Commercial Paper) (Details) - USD ($) $ in Millions	Feb. 26, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Commercial paper – issued		$ 1,263	$ 0	$ 0
Commercial paper - repayments		1,263	0	$ 0
Commercial paper outstanding		$ 0	$ 0
Commercial Paper
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 2,000
Debt instrument, term	397 days

Debt (MPC Revolving Credit Agre

Debt (MPC Revolving Credit Agreement) (Detail) $ in Millions	Jul. 20, 2016USD ($)Period	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Line of Credit Facility [Line Items]
Commercial paper – issued		$ 1,263	$ 0	$ 0
Commercial paper - repayments		$ 1,263	0	$ 0
Bank revolving credit facility due 2020
Line of Credit Facility [Line Items]
Debt instrument, term	4 years
Line of credit facility, maximum borrowing capacity	$ 2,500
Line of credit facility, expiration date	Jul. 20, 2020
Number of renewal periods | Period	2
Line of credit facility duration of renewal period	1 year
Bank revolving credit facility due 2020 | Line of Credit
Line of Credit Facility [Line Items]
Line of credit facility, expiration date		Jul. 20, 2020
Long-term debt outstanding		$ 0	0
Bank revolving credit facility due 2020 | Maximum
Line of Credit Facility [Line Items]
Line of credit facility additional borrowing capacity	$ 500
Bank revolving credit facility due 2020 | Letter of Credit
Line of Credit Facility [Line Items]
Letters of credit outstanding		$ 0
Bank revolving credit facility due 2020 | Letter of Credit | Maximum
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity	2,000
Bank revolving credit facility due 2020 | Bridge Loan | Maximum
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity	$ 100
364-day bank revolving credit facility due July 2017
Line of Credit Facility [Line Items]
Debt instrument, term	364 days
Line of credit facility, maximum borrowing capacity	$ 1,000
Line of credit facility, expiration date	Jul. 19, 2017
364-day bank revolving credit facility due July 2017 | Line of Credit
Line of Credit Facility [Line Items]
Line of credit facility, expiration date		Jul. 19, 2017
Long-term debt outstanding		$ 0	$ 0
364-day bank revolving credit facility due July 2017 | Letter of Credit
Line of Credit Facility [Line Items]
Letters of credit outstanding		$ 0
MPC bank revolving credit facilities
Line of Credit Facility [Line Items]
Debt instrument, description of variable rate basis	at either the Adjusted LIBO Rate (as defined in our revolving credit facilities) plus a margin or the Alternate Base Rate (as defined in our revolving credit facilities), plus a margin
MPC bank revolving credit facilities | Maximum
Line of Credit Facility [Line Items]
Ratio of indebtedness to net capital	0.65

Debt (Trade Receivables Securit

Debt (Trade Receivables Securitization Facility) (Details) - Trade receivables securitization facility due July 2019 - USD ($) $ in Millions	Jul. 20, 2016	Dec. 31, 2016	Jun. 30, 2016
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity	$ 750	$ 684	$ 1,000
Line of credit facility, expiration date	Jul. 19, 2019
Line of credit facility, maximum borrowing capacity	$ 750
Line of credit facility, borrowings during period		$ 430
Line of credit facility, interest rate during period		1.40%
Line of credit facility, repayments during period		$ 430

Debt (MPC Term Loan) (Details)

Debt (MPC Term Loan) (Details) - MPC Term Loan $ in Millions	Sep. 30, 2016USD ($)	Aug. 26, 2014USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 700
Debt instrument, term		5 years
Repayments of long-term debt	$ 500
Debt instrument, description of variable rate basis		Adjusted LIBO Rate (as defined in the term loan agreement) plus a margin or the Alternate Base Rate (as defined in the term loan agreement) plus a margin
Line of credit facility, interest rate during period			1.60%
Ratio of indebtedness to net capital		0.65
Unsecured Debt
Debt Instrument [Line Items]
Long-term debt outstanding			$ 200	$ 700

Debt (MPC Senior Notes) (Detail

Debt (MPC Senior Notes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 14, 2015
Debt Instrument [Line Items]
Loss on extinguishment of debt	$ 0	$ 5	$ 0
Senior Notes
Debt Instrument [Line Items]
Debt instrument, face amount				$ 1,500
Proceeds from debt		1,490
Senior Notes | Senior notes, 2.700% due December 2018
Debt Instrument [Line Items]
Debt instrument, face amount				600
Senior Notes | Senior notes, 3.400% due December 2020
Debt Instrument [Line Items]
Debt instrument, face amount				650
Senior Notes | Senior notes, 5.850% due December 2045
Debt Instrument [Line Items]
Debt instrument, face amount				$ 250
Senior Notes | Senior notes, 3.500%, due March 2016
Debt Instrument [Line Items]
Repayments of debt		750
Early repayment of senior debt		$ 763

Debt (MPLX Credit Agreement) (D

Debt (MPLX Credit Agreement) (Details) $ in Millions	Jul. 20, 2016USD ($)	Dec. 04, 2015USD ($)	Oct. 27, 2015USD ($)Period	Nov. 21, 2014	Dec. 31, 2016USD ($)	Jun. 30, 2016USD ($)	Dec. 31, 2015USD ($)
MarkWest
Debt Instrument [Line Items]
Line of credit facility, repayments during period		$ 93
Trade receivables securitization facility due July 2019
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity	$ 750				$ 684	$ 1,000
Line of credit facility, expiration date	Jul. 19, 2019
Line of credit facility, maximum borrowing capacity	$ 750
Line of credit facility, repayments during period					430
Line of credit facility, borrowings during period					$ 430
Line of credit facility, interest rate during period					1.40%
Trade receivables securitization facility due July 2019 | Letter of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 750
MPLX bank revolving credit facility due 2020 | MarkWest
Debt Instrument [Line Items]
Line of credit facility, repayments during period		850
MPLX LP | Line of Credit | MarkWest
Debt Instrument [Line Items]
Line of credit facility, repayments during period		$ 943
MPLX LP | MPLX bank revolving credit facility due 2020
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity			$ 2,000
Debt instrument, description of variable rate basis			Adjusted LIBO Rate or the Alternate Base Rate (as defined in the MPLX credit agreement)
Line of credit facility, repayments during period					$ 1,310
Line of credit facility, borrowings during period					$ 434
Line of credit facility, interest rate during period					1.90%
Remaining borrowing capacity					$ 2,000
MPLX LP | MPLX bank revolving credit facility due 2020 | Maximum
Debt Instrument [Line Items]
Line of credit facility additional borrowing capacity			$ 500
Number of prior quarterly reporting periods covenant			4
Covenant ratio debt to EBITDA			5
Covenant ratio debt to EBITDA post acquisition			5.5
MPLX LP | MPLX bank revolving credit facility due 2020 | Letter of Credit
Debt Instrument [Line Items]
Letters of credit outstanding					$ 3
MPLX LP | MPLX bank revolving credit facility due 2020 | Letter of Credit | Maximum
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity			$ 250
MPLX LP | MPLX bank revolving credit facility due 2020 | Bridge Loan | Maximum
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity			$ 100
MPLX LP | MPLX bank revolving credit facility due 2020 | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, expiration date			Dec. 4, 2020		Dec. 4, 2020
Long-term debt outstanding					$ 0		$ 877
MPLX LP | MPLX term loan facility due 2019
Debt Instrument [Line Items]
Debt instrument, term				5 years
Line of credit facility, maximum borrowing capacity			$ 250
Number of renewal periods | Period			2
Line of credit facility duration of renewal period			1 year
Debt instrument, description of variable rate basis			Adjusted LIBO Rate or the Alternate Base Rate (as defined in the MPLX Credit Agreement)
Line of credit facility, interest rate during period					2.00%
MPLX LP | MPLX term loan facility due 2019 | Maximum
Debt Instrument [Line Items]
Number of prior quarterly reporting periods covenant			4
Covenant ratio debt to EBITDA			5
Covenant ratio debt to EBITDA post acquisition			5.5
MPLX LP | MPLX term loan facility due 2019 | Unsecured Debt
Debt Instrument [Line Items]
Line of credit facility, expiration date			Nov. 20, 2019		Nov. 20, 2019
Long-term debt outstanding					$ 250		$ 250

Debt (MPLX and MarkWest Senior

Debt (MPLX and MarkWest Senior Notes) (Details) - USD ($) $ in Millions	Feb. 12, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 22, 2015	Dec. 14, 2015	Dec. 04, 2015
MarkWest
Debt Instrument [Line Items]
Long-term debt assumed						$ 4,567
Senior Notes
Debt Instrument [Line Items]
Debt instrument, face amount					$ 1,500
Proceeds from debt			$ 1,490
Senior Notes | MarkWest
Debt Instrument [Line Items]
Long-term debt assumed						$ 4,100
Debt instrument, face amount				$ 4,040
Senior Notes | MPLX LP
Debt Instrument [Line Items]
Debt instrument, face amount				4,040
Proceeds from debt			495
Senior Notes | MPLX LP | MarkWest
Debt Instrument [Line Items]
Long-term debt outstanding		$ 63	63
Senior Notes | MPLX LP | MPLX senior notes, 5.500%, due February 2023
Debt Instrument [Line Items]
Long-term debt outstanding		$ 710	710	$ 710
Debt instrument, interest rate		5.50%		5.50%
Debt instrument, maturity date		Feb. 15, 2023
Senior Notes | MPLX LP | MPLX senior notes, 5.500%, due February 2023 | MarkWest
Debt Instrument [Line Items]
Long-term debt outstanding				$ 40
Debt instrument, interest rate		5.50%		5.50%
Debt instrument, maturity date		Feb. 15, 2023
Senior Notes | MPLX LP | MPLX senior notes, 4.500%, due July 2023
Debt Instrument [Line Items]
Long-term debt outstanding		$ 989	989	$ 989
Debt instrument, interest rate		4.50%		4.50%
Debt instrument, maturity date		Jul. 15, 2023
Senior Notes | MPLX LP | MPLX senior notes, 4.500%, due July 2023 | MarkWest
Debt Instrument [Line Items]
Long-term debt outstanding				$ 11
Debt instrument, interest rate		4.50%		4.50%
Debt instrument, maturity date		Jul. 15, 2023
Senior Notes | MPLX LP | MPLX senior notes, 4.875%, due December 2024
Debt Instrument [Line Items]
Long-term debt outstanding		$ 1,149	1,149	$ 1,150
Debt instrument, interest rate		4.875%		4.875%
Debt instrument, maturity date		Dec. 1, 2024
Senior Notes | MPLX LP | MPLX senior notes, 4.875%, due December 2024 | MarkWest
Debt Instrument [Line Items]
Long-term debt outstanding				$ 1
Debt instrument, interest rate		4.875%		4.875%
Debt instrument, maturity date		Dec. 1, 2024
Senior Notes | MPLX LP | MPLX senior notes, 4.875%, due June 2025
Debt Instrument [Line Items]
Long-term debt outstanding		$ 1,189	1,189	$ 1,190
Debt instrument, interest rate		4.875%		4.875%
Debt instrument, maturity date		Jun. 1, 2025
Senior Notes | MPLX LP | MPLX senior notes, 4.875%, due June 2025 | MarkWest
Debt Instrument [Line Items]
Long-term debt outstanding				$ 11
Debt instrument, interest rate		4.875%		4.875%
Debt instrument, maturity date		Jun. 1, 2025
Senior Notes | MPLX LP | MPLX senior notes, 4.000%, due February 2025
Debt Instrument [Line Items]
Debt instrument, face amount	$ 500
Long-term debt outstanding		$ 500	$ 500
Debt instrument, interest rate	4.00%	4.00%
Debt instrument, maturity date	Feb. 15, 2025	Feb. 15, 2025

Supplemental Cash Flow Infor143

Supplemental Cash Flow Information (Summary Of Supplemental Cash Flow Information) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)	$ 478		$ 272		$ 166
Net income taxes paid to taxing authorities	140		1,605		1,362
Non-cash investing and financing activities:
Capital lease obligations increase	0		1		0
Contribution of fixed assets to joint venture	272	[1]	0		0
Property, plant and equipment sold	0		5		4
Property, plant and equipment acquired	0		5		4
Acquisition:
Fair value of MPLX units issued	$ 0		7,326	[2]	$ 0
Payable to seller			$ 50
[1]	Speedway’s contribution of travel plaza locations to new joint venture with Pilot Flying J.
[2]	See Note 5.

Supplemental Cash Flow Infor144

Supplemental Cash Flow Information (Reconciliation Of Additions To Property, Plant And Equipment To Total Capital Expenditures) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Supplemental Cash Flow Information [Abstract]
Additions to property, plant and equipment per consolidated statements of cash flows		$ 2,892		$ 1,998		$ 1,480
Non-cash additions to property, plant and equipment		0		5		4
Asset retirement expenditures		6	[1]	1	[1]	2
Increase (decrease) in capital accruals		(127)		94		95
Total capital expenditures before acquisitions		2,771		2,098		1,581
Acquisitions	[2]	(133)		11,397		2,744
Total capital expenditures	[3]	$ 2,638		$ 13,495		$ 4,325
[1]	Included in All other, net – Operating activities on the consolidated statements of cash flows.
[2]	2016 includes adjustments to the fair values of property, plant and equipment, intangibles and goodwill acquired in connection with the MarkWest Merger. The 2015 acquisitions include the MarkWest Merger. The 2014 acquisitions include the acquisition of Hess’ Retail Operations and Related Assets. The acquisition numbers above include property, plant and equipment, intangibles and goodwill. See Note 5.
[3]	Capital expenditures include changes in capital accruals. See Note 20 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 Comprehens145

Accumulated Other Comprehensive Loss (Changes in Accumulated Other Comprehensive Loss by Component) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		$ (318)	$ (313)
Other comprehensive income before reclassifications		86	(14)
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit		(49)	(50)
Amortization– actuarial loss		40	59
Amortization– settlement loss		7	4
Other		(1)
Tax effect		1	(4)
Other comprehensive income (loss)		84	(5)	$ (109)
Ending balance		(234)	(318)	(313)
Pension Benefits
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit		(46)	(46)	(46)
Other Benefits
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit		(3)	(4)	(4)
Accumulated Defined Benefit Plans Adjustment | Pension Benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(255)	(217)
Other comprehensive income before reclassifications		22	(44)
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit	[1]	(46)	(46)
Amortization– actuarial loss	[1]	38	51
Amortization– settlement loss	[1]	7	4
Tax effect		1	(3)
Other comprehensive income (loss)		22	(38)
Ending balance		(233)	(255)	(217)
Accumulated Defined Benefit Plans Adjustment | Other Benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(70)	(104)
Other comprehensive income before reclassifications		64	31
Amounts reclassified from accumulated other comprehensive loss:
Amortization - prior service credit	[1]	(3)	(4)
Amortization– actuarial loss	[1]	2	8
Amortization– settlement loss	[1]	0	0
Tax effect		0	(1)
Other comprehensive income (loss)		63	34
Ending balance		(7)	(70)	(104)
Gain on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		4	4
Other comprehensive income before reclassifications		0	0
Amounts reclassified from accumulated other comprehensive loss:
Tax effect		0	0
Other comprehensive income (loss)		0	0
Ending balance		4	4	4
Workers Compensation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		3	4
Other comprehensive income before reclassifications		0	(1)
Amounts reclassified from accumulated other comprehensive loss:
Other	[2]	(1)
Tax effect		0	0
Other comprehensive income (loss)		(1)	(1)
Ending balance		$ 2	$ 3	$ 4
[1]	These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 22.
[2]	This amount was reclassified out of accumulated other comprehensive loss and is included in selling, general and administrative on the consolidated statements of income.

Defined Benefit Pension And 146

Defined Benefit Pension And Other Postretirement Plans (Summary Of Defined Benefit Plans With Accumulated Benefit Obligations In Excess Of Plan Assets) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Projected benefit obligations	$ 2,024	$ 1,997
Accumulated benefit obligations	1,914	1,918
Fair value of plan assets	$ 1,659	$ 1,570

Defined Benefit Pension And 147

Defined Benefit Pension And Other Postretirement Plans (Summary Of Projected Benefit Obligations And Funded Status For Defined Benefit Pension And Other Postretirement Plans) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Change in plan assets:
Fair value of plan assets at January 1		$ 1,570
Fair value of plan assets at December 31		1,659		$ 1,570
Amounts recognized in the consolidated balance sheets:
Noncurrent liabilities		(1,055)		(1,179)
Pension Benefits
Change in benefit obligations:
Benefit obligations at January 1		1,997		2,075
Service cost		114		101		$ 88
Interest cost		73		71		74
Actuarial (gain) loss		15		(63)
Benefits paid		(175)		(187)
Other		0		0
Benefit obligations at December 31		2,024		1,997		2,075
Change in plan assets:
Fair value of plan assets at January 1		1,570		1,744
Actual return on plan assets		145		(33)
Employer contributions		119		46
Benefits paid		(175)		(187)
Fair value of plan assets at December 31		1,659		1,570		1,744
Funded status of plans at December 31		(365)		(427)
Amounts recognized in the consolidated balance sheets:
Current liabilities		(18)		(19)
Noncurrent liabilities		(347)		(408)
Accrued benefit cost		(365)		(427)
Pretax amounts recognized in accumulated other comprehensive loss:
Net actuarial loss		645	[1]	723
Prior service credit		(276)	[1]	(323)
Pension Benefits | LOOP LLC and Explorer Pipeline [Member]
Pretax amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	[1]	16
Other Benefits
Change in benefit obligations:
Benefit obligations at January 1		800		812
Service cost		32		31		27
Interest cost		35		32		33
Actuarial (gain) loss		(101)		(63)
Benefits paid		(26)		(24)
Other		0		12	[2]
Benefit obligations at December 31		740		800		812
Change in plan assets:
Fair value of plan assets at January 1		0		0
Actual return on plan assets		0		0
Employer contributions		26		24
Benefits paid		(26)		(24)
Fair value of plan assets at December 31		0		0		$ 0
Funded status of plans at December 31		(740)		(800)
Amounts recognized in the consolidated balance sheets:
Current liabilities		(32)		(29)
Noncurrent liabilities		(708)		(771)
Accrued benefit cost		(740)		(800)
Pretax amounts recognized in accumulated other comprehensive loss:
Net actuarial loss		17	[1]	120
Prior service credit		(6)	[1]	$ (9)
Other Benefits | LOOP LLC and Explorer Pipeline [Member]
Pretax amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	[1]	$ 1
[1]	Amounts exclude those related to LOOP and Explorer, equity method investees with defined benefit pension and postretirement plans for which net losses of $16 million and less than $1 million were recorded in accumulated other comprehensive loss in 2016, reflecting our ownership share.
[2]	Includes adjustments related to the MarkWest Merger in 2015.

Defined Benefit Pension And 148

Defined Benefit Pension And Other Postretirement Plans (Components Of Net Periodic Benefit Cost And Other Comprehensive Loss) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Other changes in plan assets and benefit obligations recognized in other comprehensive loss (pretax):
Amortization of prior service cost		$ 49	$ 50
Pension Benefits
Components of net periodic benefit cost:
Service cost		114	101		$ 88
Interest cost		73	71		74
Expected return on plan assets		(98)	(98)		(107)
Amortization – prior service credit		(46)	(46)		(46)
Amortization – actuarial loss		38	51		51
Amortization – settlement loss		7	4		96
Net periodic benefit cost	[1]	88	83		156
Other changes in plan assets and benefit obligations recognized in other comprehensive loss (pretax):
Actuarial (gain) loss		(33)	69		188
Prior service cost (credit)		0	0		0
Amortization of actuarial loss		(45)	(55)		(147)
Amortization of prior service cost		46	46		46
Other		0	0		0
Total recognized in other comprehensive loss		(32)	60		87
Total recognized in net periodic benefit cost and other comprehensive loss		56	143		243
Estimated net gain (loss) that will be amortized from accumulated other comprehensive loss in 2017		35
Estimated prior service cost that will be amortized from accumulated other comprehensive loss in 2017		39
Other Benefits
Components of net periodic benefit cost:
Service cost		32	31		27
Interest cost		35	32		33
Expected return on plan assets		0	0		0
Amortization – prior service credit		(3)	(4)		(4)
Amortization – actuarial loss		2	8		2
Amortization – settlement loss		0	0		0
Net periodic benefit cost	[1]	66	67		58
Other changes in plan assets and benefit obligations recognized in other comprehensive loss (pretax):
Actuarial (gain) loss		(101)	(63)		86
Prior service cost (credit)		0	13	[2]	0
Amortization of actuarial loss		(2)	(8)		(2)
Amortization of prior service cost		3	4		4
Other		0	0		0
Total recognized in other comprehensive loss		(100)	(54)		88
Total recognized in net periodic benefit cost and other comprehensive loss		(34)	$ 13		$ 146
Estimated net gain (loss) that will be amortized from accumulated other comprehensive loss in 2017		2
Estimated prior service cost that will be amortized from accumulated other comprehensive loss in 2017		$ 3
[1]	Net periodic benefit cost reflects a calculated market-related value of plan assets which recognizes changes in fair value over three years.
[2]	Includes adjustments related to the MarkWest Merger in 2015

Defined Benefit Pension And 149

Defined Benefit Pension And Other Postretirement Plans (Summary Of Assumptions Used To Determine Benefit Obligations And Net Periodic Benefit Cost) (Detail)		1 Months Ended	12 Months Ended
		Jan. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits
Weighted-average assumptions used to determine benefit obligation:
Discount rate			3.90%	4.00%	3.65%
Rate of compensation increase			5.00%	3.70%	3.70%
Weighted-average assumptions used to determine net periodic benefit cost:
Discount rate			3.80%	3.70%	4.05%
Expected long-term return on plan assets	[1]		6.50%	6.75%	7.00%
Rate of compensation increase			5.00%	3.70%	3.70%
Pension Benefits | Scenario, Forecast
Weighted-average assumptions used to determine net periodic benefit cost:
Expected long-term return on plan assets	[1]	6.50%
Other Benefits
Weighted-average assumptions used to determine benefit obligation:
Discount rate			4.25%	4.50%	4.15%
Rate of compensation increase			5.00%	3.70%	3.70%
Weighted-average assumptions used to determine net periodic benefit cost:
Discount rate			4.50%	4.30%	4.95%
Expected long-term return on plan assets	[1]		0.00%	0.00%	0.00%
Rate of compensation increase			5.00%	3.70%	3.70%
[1]	Effective January 1, 2017, the expected long-term rate of return on plan assets is 6.50 percent due to a continuation of a change in our primary plan investment strategy, which began January 1, 2014.

Defined Benefit Pension and 150

Defined Benefit Pension and Other Postretirement Plans (Expected Long-Term Return on Plan Assets) (Details)	12 Months Ended
	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Defined benefit plan, investment goals	The overall expected long-term return on plan assets assumption is determined based on an asset rate-of-return modeling tool developed by a third-party investment group. The tool utilizes underlying assumptions based on actual returns by asset category and inflation and takes into account our asset allocation to derive an expected long-term rate of return on those assets. Capital market assumptions reflect the long-term capital market outlook. The assumptions for equity and fixed income investments are developed using a building-block approach, reflecting observable inflation information and interest rate information available in the fixed income markets. Long-term assumptions for other asset categories are based on historical results, current market characteristics and the professional judgment of our internal and external investment teams.

Defined Benefit Pension And 151

Defined Benefit Pension And Other Postretirement Plans (Summarizes Assumed Health Care Cost Trend Rates) (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Medical Pre-65
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for the following year:	7.00%	7.50%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate):	4.50%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate:	2,026	2,021	2,021
Prescription drugs
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for the following year:	9.00%	7.00%	7.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate):	4.50%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate:	2,026	2,021	2,021
Medical Post-65 | Maximum
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for the following year:	4.00%

Defined Benefit Pension And 152

Defined Benefit Pension And Other Postretirement Plans (Effects Of One Percentage Point Change In Assumed Health Care Cost Trend Rates) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Effect on total of service and interest cost components, 1-Percentage-Point-Increase	$ 6
Effect on other postretirement benefit obligations, 1-Percentage-Point-Increase	33
Effect on total of service and interest cost components, 1-Percentage-Point Decrease	(5)
Effect on other postretirement benefit obligations, 1-Percentage-Point-Decrease	$ (29)

Defined Benefit Pension and 153

Defined Benefit Pension and Other Postretirement Plans (Plan Investment Policies And Strategies) (Details)	12 Months Ended
	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, diversification	The asset allocation strategy will change over time in response to changes primarily in funded status, which is dictated by current and anticipated market conditions, the independent actions of our investment committee, required cash flows to and from the plans and other factors deemed appropriate. Such changes in asset allocation are intended to allocate additional assets to the fixed income asset class should the funded status improve. The fixed income asset class shall be invested in such a manner that its interest rate sensitivity correlates highly with that of the plans’ liabilities. Other asset classes are intended to provide additional return with associated higher levels of risk.
Plan investment policies and strategies	Investment performance and risk is measured and monitored on an ongoing basis through quarterly investment meetings and periodic asset and liability studies.
Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Targeted asset allocation	51.00%
Fixed Income Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Targeted asset allocation	49.00%

Defined Benefit Pension And 154

Defined Benefit Pension And Other Postretirement Plans (Fair Values Of Defined Benefit Pension Plan Assets) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	$ 1,659	$ 1,570
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	24	27
Equity investments, common stocks
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	71	57
Equity funds, mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	160	142
Equity funds, pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	451	399
Fixed income, corporate
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	570	516
Fixed income, government
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	90	103
Fixed income, pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	173	193
Private equity
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	60	62
Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	39	50
Other
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	21	21
Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	233	201
Level 1 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 1 | Equity investments, common stocks
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	71	57
Level 1 | Equity funds, mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	160	142
Level 1 | Equity funds, pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 1 | Fixed income, corporate
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 1 | Fixed income, government
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 1 | Fixed income, pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 1 | Private equity
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 1 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	2	2
Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	1,308	1,238
Level 2 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	24	27
Level 2 | Equity investments, common stocks
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 2 | Equity funds, mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 2 | Equity funds, pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	451	399
Level 2 | Fixed income, corporate
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	570	516
Level 2 | Fixed income, government
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	90	103
Level 2 | Fixed income, pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	173	193
Level 2 | Private equity
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 2 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 2 | Other
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 3
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	118	131	$ 144
Level 3 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 3 | Equity investments, common stocks
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 3 | Equity funds, mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 3 | Equity funds, pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 3 | Fixed income, corporate
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 3 | Fixed income, government
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 3 | Fixed income, pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	0	0
Level 3 | Private equity
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	60	62	66
Level 3 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	39	50	57
Level 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Plan asset investments, at fair value	$ 19	$ 19	$ 21

Defined Benefit Pension And 155

Defined Benefit Pension And Other Postretirement Plans (Reconciliation Of Beginning And Ending Balances Of Plan Assets Classified As Level 3) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	$ 1,570
Actual return on plan assets:
Fair value of plan assets at December 31	1,659	$ 1,570
Private equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	62
Actual return on plan assets:
Fair value of plan assets at December 31	60	62
Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	50
Actual return on plan assets:
Fair value of plan assets at December 31	39	50
Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	21
Actual return on plan assets:
Fair value of plan assets at December 31	21	21
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	131	144
Actual return on plan assets:
Realized	13	18
Unrealized	(1)	(6)
Purchases	3	10
Sales	(28)	(35)
Fair value of plan assets at December 31	118	131
Level 3 | Private equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	62	66
Actual return on plan assets:
Realized	8	12
Unrealized	2	(1)
Purchases	2	5
Sales	(14)	(20)
Fair value of plan assets at December 31	60	62
Level 3 | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	50	57
Actual return on plan assets:
Realized	5	6
Unrealized	(3)	(3)
Purchases	1	5
Sales	(14)	(15)
Fair value of plan assets at December 31	39	50
Level 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	19	21
Actual return on plan assets:
Realized	0	0
Unrealized	0	(2)
Purchases	0	0
Sales	0	0
Fair value of plan assets at December 31	$ 19	$ 19

Defined Benefit Pension and 156

Defined Benefit Pension and Other Postretirement Plans (Contributions To Defined Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to defined contribution plans	$ 113	$ 94	$ 86
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension contributions	119
Unfunded Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plans, estimated future employer contributions in next fiscal year	14
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plans, estimated future employer contributions in next fiscal year	$ 32

Defined Benefit Pension And 157

Defined Benefit Pension And Other Postretirement Plans (Estimated Future Benefit Payments) (Detail) $ in Millions	Dec. 31, 2016USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
2,017	$ 174
2,018	177
2,019	182
2,020	165
2,021	165
2022 through 2026	801
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
2,017	32
2,018	35
2,019	37
2,020	39
2,021	41
2022 through 2026	$ 222

Defined Benefit Pension And 158

Defined Benefit Pension And Other Postretirement Plans (Multiemployee Plans) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)Plan	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Defined Benefit Plan Disclosure [Line Items]
Multiemployer pension plans percentage funded	65.00%
Marathon Petroleum's contributions as a percentage of total contributions to the multi-employer pension plan, maximum	5.00%
Multiemployer Plans, Pension
Defined Benefit Plan Disclosure [Line Items]
Number of multiemployer defined benefit pension or health and welfare plan	1
Multi employer pension plans	There have been no significant changes that affect the comparability of 2016 , 2015 and 2014 contributions.
Multiemployer Plans, Postretirement Benefit
Defined Benefit Plan Disclosure [Line Items]
Number of multiemployer defined benefit pension or health and welfare plan	1
MPC contributions | $	$ 6	$ 7	$ 6

Defined Benefit Pension And 159

Defined Benefit Pension And Other Postretirement Plans (Multi Employer Pension Plan) (Detail) - Multiemployer Plans, Pension	12 Months Ended
	Dec. 31, 2016USD ($)Employee		Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Multiemployer Plans [Line Items]
Multiemployer pension plan, minimum contribution requirement per week per employee	$ 303
Number of employees participated in the plan | Employee	280
Central States, Southeast and Southwest Pension Plan [Member]
Multiemployer Plans [Line Items]
MPC contributions	$ 4,000,000	[1]	$ 4,000,000	$ 4,000,000
[1]	This agreement has a minimum contribution requirement of $303 per week per employee for 2017. A total of 280 employees participated in the plan as of December 31, 2016.

Stock-Based Compensation Pla160

Stock-Based Compensation Plans (Narrative) (Detail) shares in Millions	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, expiration period	10 years
Vesting period of awards	3 years
Restricted Stock Awards and Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards	3 years
Restricted stock and restricted stock unit awards granted in 2012, additional holding period	1 year
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target payout | $ / shares	$ 1
Maximum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Actual payout | $ / shares	$ 2
Target payout percentage	200.00%
MPC 2012 Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock authorized to be delivered under the compensation plan	50
MPC 2012 Plan | Maximum | Awards Other Than Stock Options Or Stock Appreciation Rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock authorized to be delivered under the compensation plan	20
MPC 2012 Plan | Maximum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock authorized to be delivered under the compensation plan	20
MPC 2012 and 2011 Plans | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards	36 months
Pay-out percentage in MPC common stock (in percentage)	25.00%
Pay-out percentage in cash (in percentage)	75.00%

Stock-Based Compensation Pla161

Stock-Based Compensation Plans (Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense	$ 45	$ 42	$ 40
Tax benefit recognized on stock-based compensation expense	17	16	15
Cash received by MPC upon exercise of stock option awards	10	33	26
Tax benefit received for tax deductions for stock awards exercised	$ 4	$ 26	$ 19

Stock-Based Compensation Pla162

Stock-Based Compensation Plans (Weighted Average Assumptions Used To Value Stock Options Awards) (Detail) - Stock Options - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price per share	$ 35.27	$ 50.85	$ 42.51
Expected life in years	6 years 2 months 14 days	6 years	5 years 9 months 19 days
Expected volatility	38.00%	33.00%	36.00%
Expected dividend yield	3.00%	2.00%	1.90%
Risk-free interest rate	1.40%	1.70%	1.80%
Weighted average grant date fair value of stock option awards granted	$ 9.84	$ 13.44	$ 12.69
Implied volatility rate weighting (in percentage)	50.00%
Historical volatility rate weighting (in percentage)	50.00%

Stock-Based Compensation Pla163

Stock-Based Compensation Plans (Summary Of Stock Option Award Activity) (Detail) - Stock Options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	$ 14	$ 60	$ 48
Unrecognized compensation cost	$ 8
Weighted average recognition period, in years	1 year 6 months 3 days
Number of Shares
Outstanding, beginning balance	8,724,631
Granted	1,474,177
Exercised	(637,761)
Forfeited, canceled or expired	(29,607)
Outstanding, ending balance	9,531,440	8,724,631
Vested and expected to vest at December 31, 2016 (in shares)	9,518,269
Exercisable at December 31, 2016 (in shares)	7,094,204
Weighted Average Exercise Price
Outstanding, beginning balance (in USD per share)	$ 27.16
Granted (in USD per share)	35.27	$ 50.85	$ 42.51
Exercised (in USD per share)	18.78
Forfeited, canceled or expired (in USD per share)	42.91
Outstanding, ending balance (in USD per share)	28.93	$ 27.16
Vested and expected to vest at December 31, 2016 (in USD per share)	28.90
Exercisable at December 31, 2016 (in USD per share)	$ 24.90
Weighted Average Remaining Contractual Terms (in years)
Vested and expected to vest at December 31, 2016 (in years)	5 years 4 months 8 days
Exercisable at December 31, 2016 (in years)	4 years 3 months 1 day
Aggregate Intrinsic Value (in millions)
Vested and expected to vest at December 31, 2016 (in USD)	$ 205
Exercisable at December 31, 2016 (in USD)	$ 181

Stock-Based Compensation Pla164

Stock-Based Compensation Plans (Summary Of Restricted Stock Award Activity) (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted units outstanding	361,117
Restricted Stock
Number of Shares
Outstanding, beginning balance	1,074,543
Granted	732,074
RS’s Vested/RSU’s Issued	(477,339)
Forfeited	(78,935)
Outstanding, ending balance	1,250,343	1,074,543
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share)	$ 47.70
Granted (in USD per share)	36.17	$ 50.64	$ 43.82
RS's Vested/RSU's Issued (in USD per share)	46.26
Forfeited (in USD per share)	47.53
Outstanding, ending balance (in USD per share)	$ 41.51	$ 47.70
Restricted Stock Units
Number of Shares
Outstanding, beginning balance	513,220
Granted	45,495
RS’s Vested/RSU’s Issued	(197,598)
Forfeited	0
Outstanding, ending balance	361,117	513,220
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share)	$ 24.59
Granted (in USD per share)	40.85	$ 49.87	$ 42.95
RS's Vested/RSU's Issued (in USD per share)	21.62
Forfeited (in USD per share)	0
Outstanding, ending balance (in USD per share)	$ 28.26	$ 24.59
Non-Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted units vested	343,327
Weighted average fair value, vested	$ 27.25

Stock-Based Compensation Pla165

Stock-Based Compensation Plans (Summary Of Values Related To Vested And Unvested Restricted Stock Awards) (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic Value of Awards Vested During the Period (in millions)	$ 17	$ 27	$ 28
Weighted Average Grant Date Fair Value of Awards Granted During the Period	$ 36.17	$ 50.64	$ 43.82
Unrecognized compensation cost	$ 34
Weighted average recognition period, in years	1 year 6 months 3 days
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic Value of Awards Vested During the Period (in millions)	$ 8	$ 21	$ 0
Weighted Average Grant Date Fair Value of Awards Granted During the Period	$ 40.85	$ 49.87	$ 42.95
Unrecognized compensation cost	$ 0

Stock-Based Compensation Pla166

Stock-Based Compensation Plans (Summary Of Performance Unit Awards) (Detail) - Performance Shares - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued in period	124,234
Unrecognized compensation cost	$ 2
Weighted average recognition period, in years	1 year 6 months 12 days
Number of Shares
Outstanding, beginning balance	6,145,442
Granted	2,329,500
Exercised	(1,904,792)
Canceled	(314,972)
Outstanding, ending balance	6,255,178	6,145,442
Weighted Average Grant Date Fair Value
Outstanding, beginning balance (in USD per share)	$ 0.92
Granted (in USD per share)	0.57	$ 0.95	$ 0.85
Exercised (in USD per share)	0.95
Canceled (in USD per share)	0.93
Outstanding, ending balance (in USD per share)	$ 0.78	$ 0.92

Stock-Based Compensation Pla167

Stock-Based Compensation Plans (Weighted Average Assumptions Used to Value Performance Unit Awards) (Details) - Performance Shares - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0.96%	0.95%	0.63%
Look-back period	2 years 9 months 30 days	2 years 10 months 3 days	2 years 10 months 3 days
Expected volatility	34.15%	30.38%	38.51%
Grant date fair value of performance units granted	$ 0.57	$ 0.95	$ 0.85

Leases (Schedule Of Future Mini

Leases (Schedule Of Future Minimum Commitments) (Detail) $ in Millions	Dec. 31, 2016USD ($)
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,017	$ 50
2,018	50
2,019	45
2,020	49
2,021	45
Later years	206
Total minimum lease payments	445
Less imputed interest costs	(126)
Present value of net minimum lease payments	319
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,017	254
2,018	211
2,019	198
2,020	188
2,021	170
Later years	569
Total minimum lease payments	$ 1,590

Leases (Schedule Of Operating L

Leases (Schedule Of Operating Lease Rental Expense) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Leases [Abstract]
Rental expense	$ 327	$ 331	$ 256

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Leases [Abstract]
Operating lease revenue	$ 246	$ 16	$ 0
Contingent lease payments received	$ 7	$ 1

Leases (Minimum Future Rentals

Leases (Minimum Future Rentals On The Non-Cancellable Operating Leases) (Details) $ in Millions	Dec. 31, 2016USD ($)
Leases [Abstract]
2,017	$ 197
2,018	200
2,019	202
2,020	201
2,021	185
Later years	460
Total minimum lease payments	$ 1,445

Leases (Investments In Assets H

Leases (Investments In Assets Held For Operating Lease By Major Classes) (Details) $ in Millions	Dec. 31, 2016USD ($)
Operating Leased Assets [Line Items]
Property, plant and equipment, gross	$ 1,713
Less accumulated depreciation	84
Property, plant and equipment, net	1,629
Natural gas gathering and NGL transportation pipelines and facilities
Operating Leased Assets [Line Items]
Property, plant and equipment, gross	650
Natural gas processing facilities
Operating Leased Assets [Line Items]
Property, plant and equipment, gross	844
Construction in progress
Operating Leased Assets [Line Items]
Property, plant and equipment, gross	$ 219

Commitments and Contingencies (

Commitments and Contingencies (Detail)	12 Months Ended
	Dec. 31, 2016
Pending Litigation
Loss Contingencies [Line Items]
Loss contingency, inestimable loss	For matters for which we have not recorded an accrued liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings and discovery.

Commitments and Contingencie174

Commitments and Contingencies (Environmental Matters) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Accrued liabilities for remediation	$ 132	$ 163
Receivables for recoverable costs	$ 58	$ 70

Commitments and Contingencie175

Commitments and Contingencies (MarkWest Environmental Proceedings) (Details) - MarkWest Liberty Midstream Pipeline Launcher/Receiver Site [Member] - Pending Litigation $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Cash
Loss Contingencies [Line Items]
Proposed settlement	$ 2.4
Other Liabilities
Loss Contingencies [Line Items]
Proposed settlement	$ 3.6

Commitments and Contingencie176

Commitments and Contingencies (Lawsuits) (Details) - Emergency Pricing And Consumer Protection Laws - Pending Litigation $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Loss Contingencies [Line Items]
Plaintiff	Commonwealth of Kentucky
Alleged amount overcharged from customers	$ 89
Loss contingency, period of occurrence	during September and October 2005

Commitments and Contingencie177

Commitments and Contingencies (Guarantees) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	May 31, 2016	Sep. 30, 2015
Centennial
Loss Contingencies [Line Items]
Equity method investments, ownership percentage	50.00%
Crowley Ocean Partners
Loss Contingencies [Line Items]
Equity method investments, ownership percentage	50.00%	50.00%	50.00%
Crowley Blue Water Partners
Loss Contingencies [Line Items]
Equity method investments, ownership percentage	50.00%
Financial Guarantee | Centennial
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	$ 29
Financial Guarantee | Master Shelf Agreement | Centennial
Loss Contingencies [Line Items]
Line of credit facility, expiration date	Dec. 31, 2024
Financial Guarantee | Guarantee of Indebtedness of Others | LOOP and LOCAP LLC
Loss Contingencies [Line Items]
Line of credit facility, expiration date	Dec. 31, 2037
Financial Guarantee | Guarantee of Indebtedness of Others | Crowley Ocean Partners | Crowley Term Loan [Member]
Loss Contingencies [Line Items]
Line of credit facility, maximum borrowing capacity	$ 325
Indemnification Agreement | Marathon Oil Companies
Loss Contingencies [Line Items]
Guarantee obligation current carrying value	2
Other Guarantees
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	82
Guarantee obligations maximum exposure per event	50
Guarantee of Indebtedness of Others | Financial Guarantee | LOOP and LOCAP LLC
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	172
Guarantee of Indebtedness of Others | Financial Guarantee | Crowley Ocean Partners
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	163
Guarantee of Indebtedness of Others | Financial Guarantee | Crowley Blue Water Partners
Loss Contingencies [Line Items]
Maximum potential undiscounted payments	$ 142

Commitments and Contingences (C

Commitments and Contingences (Contractual Commitments and Contingencies) (Details) - USD ($) $ in Millions	12 Months Ended		30 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
Loss Contingencies [Line Items]
Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees	$ 899	$ 1,600
North Dakota Pipeline
Loss Contingencies [Line Items]
Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees		630
Crowley Ocean Partners
Loss Contingencies [Line Items]
Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees		69
Galveston Bay Refinery and Related Assets
Loss Contingencies [Line Items]
Contractual commitments to acquire property, plant and equipment and advance funds to equity method investees	$ 131	$ 331	$ 131

Subsequent Events (Details)

Subsequent Events (Details) bbl / d in Thousands, $ in Millions		Feb. 13, 2017USD ($)bbl / dmiin	Feb. 10, 2017USD ($)	Feb. 06, 2017USD ($)	Dec. 31, 2016USD ($)		Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Subsequent Event [Line Items]
Contribution of fixed assets to joint venture					$ 272	[1]	$ 0	$ 0
Additions to property, plant and equipment					$ (2,892)		$ (1,998)	$ (1,480)
Subsequent Event | MPLX LP | Senior Notes | Senior Notes Due March 2027
Subsequent Event [Line Items]
Long-term debt, gross			$ 1,250
Debt instrument, interest rate			4.125%
Debt instrument, maturity date			Mar. 1, 2027
Subsequent Event | MPLX LP | Senior Notes | Senior Notes Due March 2047
Subsequent Event [Line Items]
Long-term debt, gross			$ 1,000
Debt instrument, interest rate			5.20%
Debt instrument, maturity date			Mar. 1, 2047
Sherwood Midstream | Subsequent Event | MPLX LP
Subsequent Event [Line Items]
Contribution of fixed assets to joint venture	[1]			$ 134
Sherwood Midstream | Subsequent Event | Antero Midstream Partners L.P.
Subsequent Event [Line Items]
Payments to acquire interest in joint venture	[1]			$ 154
Ozark Pipeline | Subsequent Event
Subsequent Event [Line Items]
Pipeline length | mi		433
Pipeline diameter | in		22
Crude oil throughput | bbl / d		230
Ozark Pipeline | Subsequent Event | MPLX LP
Subsequent Event [Line Items]
Additions to property, plant and equipment		$ (220)
[1]	Speedway’s contribution of travel plaza locations to new joint venture with Pilot Flying J.

Selected Quarterly Financial180

Selected Quarterly Financial Data (Schedule Of Quarterly Financial Information) (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Revenues	$ 17,155	$ 16,618	$ 16,811	$ 12,755	$ 15,607	$ 18,716	$ 20,537	$ 17,191
Income from operations	553	435	1,315	75	338	1,549	1,335	1,470		$ 2,378	$ 4,692	$ 4,051
Net income	289	219	783	(78)	168	958	839	903		1,213	2,868	2,555
Net income attributable to MPC	$ 227	$ 145	$ 801	$ 1	$ 187	$ 948	$ 826	$ 891		$ 1,174	$ 2,852	$ 2,524
Net income attributable to MPC per share:
Basic (in USD per share)	$ 0.43	$ 0.28	$ 1.51	$ 0.003	$ 0.35	$ 1.77	$ 1.52	$ 1.63	[1]	$ 2.22	$ 5.29	$ 4.42
Diluted (in USD per share)	0.43	0.27	1.51	0.003	0.35	1.76	1.51	1.62	[1]	2.21	5.26	4.39
Dividends paid per share (in USD per share)	$ 0.36	$ 0.36	$ 0.32	$ 0.32	$ 0.32	$ 0.32	$ 0.25	$ 0.25	[1]	$ 1.36	$ 1.14	$ 0.92
[1]	We completed a two-for-one stock split in June 2015. All historical per share data has been retroactively restated on a post-split basis.

Supplementary Statistics (Suppl

Supplementary Statistics (Supplementary Statistics) (Detail) - USD ($) $ in Millions		Dec. 04, 2015	Sep. 30, 2014	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Supplementary Statistics [Line Items]
Income from operations				$ 553	$ 435	$ 1,315	$ 75	$ 338	$ 1,549	$ 1,335	$ 1,470	$ 2,378		$ 4,692		$ 4,051
Segment capital expenditures and investments												3,069		16,283		4,738
Inventory market valuation adjustment												(370)		370		0
Hess Retail Operations and Related Assets
Supplementary Statistics [Line Items]
Segment capital expenditures and investments																2,710
Refining & Marketing
Supplementary Statistics [Line Items]
Inventory market valuation adjustment	[1]											(345)		345
Speedway
Supplementary Statistics [Line Items]
Inventory market valuation adjustment	[1]											(25)		25
Operating Segments
Supplementary Statistics [Line Items]
Income from operations												3,148		5,139		4,424
Segment capital expenditures and investments												2,925		16,091		4,628
Operating Segments | Refining & Marketing
Supplementary Statistics [Line Items]
Income from operations												1,543	[2]	4,086	[2]	3,538
Segment capital expenditures and investments	[3]											1,101		1,045		1,043	[4]
Operating Segments | Refining & Marketing | Hess Retail Operations and Related Assets
Supplementary Statistics [Line Items]
Segment capital expenditures and investments			$ 52
Operating Segments | Speedway
Supplementary Statistics [Line Items]
Income from operations												734	[2]	673	[2]	544
Segment capital expenditures and investments	[3]											303		501		2,981	[4]
Operating Segments | Speedway | Hess Retail Operations and Related Assets
Supplementary Statistics [Line Items]
Segment capital expenditures and investments			$ 2,660
Operating Segments | Midstream
Supplementary Statistics [Line Items]
Income from operations	[5]											871		380		342
Segment capital expenditures and investments	[3]											1,521		14,545	[6]	604
Operating Segments | Midstream | MarkWest
Supplementary Statistics [Line Items]
Segment capital expenditures and investments		$ 13,850
Operating Segments | Midstream | MPLX LP
Supplementary Statistics [Line Items]
Cost of services, overhead												11		20		19
Corporate and Other
Supplementary Statistics [Line Items]
Income from operations	[7]											(277)		(299)		(277)
Segment capital expenditures and investments	[3],[8]											144		192		110
Capitalized interest												63		37		27
Segment Reconciling Items
Supplementary Statistics [Line Items]
Pension settlement expenses	[9]											(7)		(4)		(96)
Impairment												$ (486)	[1]	$ (144)	[1]	$ 0
[1]	2016 includes impairments of goodwill and equity method investments. 2015 relates to the cancellation of the ROUX project at our Garyville refinery. See Notes 15, 16 and 17.
[2]	he Refining & Marketing and Speedway segments include an inventory LCM charge of $345 million and $25 million, respectively.
[3]	Capital expenditures include changes in capital accruals, acquisitions and investments in affiliates.
[4]	The Speedway and Refining & Marketing segments include $2.66 billion and $52 million, respectively, for the acquisition of Hess’ Retail Operations and Related Assets. See Note 5.
[5]	Included in the Midstream segment for 2016, 2015 and 2014 are $11 million, $20 million and $19 million, respectively, of corporate overhead expenses attributable to MPLX. The remaining corporate overhead expenses are not currently allocated to other segments, but instead are reported in corporate and other unallocated items. Also included in the Midstream segment for 2015 are $36 million of transaction costs related to the MarkWest Merger.
[6]	The Midstream segment includes $13.85 billion for the MarkWest Merger. See Note 5.
[7]	Included in the Midstream segment for 2016, 2015 and 2014 are $11 million, $20 million and $19 million of corporate overhead expenses attributable to MPLX. The remaining corporate overhead expenses are not currently allocated to other segments, but instead reported in corporate and other unallocated items.
[8]	Includes capitalized interest of $63 million, $37 million and $27 million for 2016, 2015 and 2014, respectively.
[9]	See Note 22.

Supplementary Statistics (Opera

Supplementary Statistics (Operating Statistics) (Detail) bbl / d in Thousands, gal in Millions, CFPD in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2016USD ($)Storebbl / dCFPD$ / bbl$ / galgal		Dec. 31, 2015USD ($)Storebbl / dCFPD$ / bbl$ / galgal		Dec. 31, 2014USD ($)Storebbl / d$ / bbl$ / galgal
Operating Statistics [Line Items ]
MPC Consolidated Refined Product Sales Volumes (thousands of barrels per day)	[1]	2,269		2,301		2,138
Refining & Marketing
Refining & Marketing Operating Statistics
Refining & Marketing refined product sales volume (thousands of barrels per day)	[2]	2,259		2,289		2,125
Refining & Marketing gross margin (dollars per barrel) | $ / bbl	[4]	11.26	[3]	15.25	[3]	15.05
Crude oil capacity utilization percent	[5]	95.00%		99.00%		95.00%
Refinery throughputs (thousands of barrels per day)	[6]	1,850		1,888		1,806
Inter-refinery transfers		83		46		43
Sour crude oil throughput percent		60.00%		55.00%		52.00%
WTI-priced crude oil throughput percent		19.00%		20.00%		19.00%
Refined product yields (thousands of barrels per day)	[6]	1,883		1,919		1,839
Refinery direct operating costs (dollars per barrel):
Planned turnaround and major maintenance | $ / bbl	[7]	1.83		1.13		1.80
Depreciation and amortization | $ / bbl	[7]	1.47		1.39		1.41
Other manufacturing | $ / bbl	[7],[8]	4.09		4.15		4.86
Total | $ / bbl	[7]	7.39		6.67		8.07
Refining & Marketing | Crude oil refined
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[6]	1,699		1,711		1,622
Refining & Marketing | Other charge and blendstocks
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[6]	151		177		184
Refining & Marketing | Gasoline
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	900		913		869
Refining & Marketing | Distillates
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	617		603		580
Refining & Marketing | Propane
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	35		36		35
Refining & Marketing | Feedstocks and special products
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	241		281		276
Refining & Marketing | Heavy fuel oil
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	32		31		25
Refining & Marketing | Asphalt
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[6]	58		55		54
Refining & Marketing | Gulf Coast:
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	1,234		1,244		1,173
Sour crude oil throughput percent		73.00%		68.00%		64.00%
WTI-priced crude oil throughput percent		8.00%		6.00%		3.00%
Refined product yields (thousands of barrels per day)	[9]	1,261		1,269		1,199
Refinery direct operating costs (dollars per barrel):
Planned turnaround and major maintenance | $ / bbl	[7]	2.09		0.81		1.82
Depreciation and amortization | $ / bbl	[7]	1.14		1.09		1.15
Other manufacturing | $ / bbl	[7],[8]	3.70		3.88		4.73
Total | $ / bbl	[7]	6.93		5.78		7.70
Refining & Marketing | Gulf Coast: | Crude oil refined
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	1,039		1,060		991
Refining & Marketing | Gulf Coast: | Other charge and blendstocks
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	195		184		182
Refining & Marketing | Gulf Coast: | Gasoline
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	514		534		508
Refining & Marketing | Gulf Coast: | Distillates
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	399		392		368
Refining & Marketing | Gulf Coast: | Propane
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	26		26		23
Refining & Marketing | Gulf Coast: | Feedstocks and special products
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	286		286		274
Refining & Marketing | Gulf Coast: | Heavy fuel oil
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	21		15		13
Refining & Marketing | Gulf Coast: | Asphalt
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	15		16		13
Refining & Marketing | Midwest:
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	699		690		676
Sour crude oil throughput percent		40.00%		34.00%		33.00%
WTI-priced crude oil throughput percent		38.00%		43.00%		44.00%
Refined product yields (thousands of barrels per day)	[9]	705		696		683
Refinery direct operating costs (dollars per barrel):
Planned turnaround and major maintenance | $ / bbl	[7]	1.15		1.64		1.66
Depreciation and amortization | $ / bbl	[7]	1.88		1.83		1.78
Other manufacturing | $ / bbl	[7],[8]	4.29		4.36		4.76
Total | $ / bbl	[7]	7.32		7.83		8.20
Refining & Marketing | Midwest: | Crude oil refined
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	660		651		631
Refining & Marketing | Midwest: | Other charge and blendstocks
Refining & Marketing Operating Statistics
Refinery throughputs (thousands of barrels per day)	[9]	39		39		45
Refining & Marketing | Midwest: | Gasoline
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	386		379		361
Refining & Marketing | Midwest: | Distillates
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	218		211		212
Refining & Marketing | Midwest: | Propane
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	11		12		13
Refining & Marketing | Midwest: | Feedstocks and special products
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	35		38		43
Refining & Marketing | Midwest: | Heavy fuel oil
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	12		17		13
Refining & Marketing | Midwest: | Asphalt
Refining & Marketing Operating Statistics
Refined product yields (thousands of barrels per day)	[9]	43		39		41
Speedway
Speedway Operating Statistics(j)
Convenience stores at period-end | Store	[10]	2,733		2,766		2,746
Gasoline and distillate sales (millions of gallons) | gal	[10]	6,094		6,038		3,942
Gasoline and distillate gross margin (dollars per gallon) | $ / gal	[10],[11]	0.1656	[3]	0.1823	[3]	0.1775
Merchandise sales (in millions) | $	[10]	$ 5,007		$ 4,879		$ 3,611
Merchandise gross margin (in millions) | $	[10]	$ 1,435		$ 1,368		$ 975
Merchandise margin percent	[10]	28.70%		28.00%		27.00%
Same store gasoline sales volume (period over period) percentage	[10]	(0.40%)		(0.30%)		(0.70%)
Merchandise sales excluding cigarettes (period over period) percentage	[10],[12]	3.20%		4.10%		5.00%
Midstream
Midstream Operating Statistics
Crude oil and refined product pipeline throughputs (thousands of barrels per day)	[13]	2,311		2,191		2,119
Gathering system throughput (million cubic feet per day) | CFPD	[14]	3,275		3,075
Natural gas processed (million cubic feet per day) | CFPD	[14]	5,761		5,468
C2 (ethane) and NGLs (natural gas liquids) fractionated (mbpd)	[14]	335		307
[1]	Total average daily volumes of refined product sales to wholesale, branded and retail customers.
[2]	Includes intersegment sales.
[3]	Excludes the lower of cost or market adjustment.
[4]	Sales revenue less cost of refinery inputs and purchased products, divided by total refinery throughputs.
[5]	Based on calendar day capacity, which is an annual average that includes downtime for planned maintenance and other normal operating activities.
[6]	Excludes inter-refinery volumes of 83 mbpd, 46 mbpd and 43 mbpd for 2016, 2015 and 2014, respectively
[7]	Per barrel of total refinery throughputs.
[8]	Includes utilities, labor, routine maintenance and other operating costs.
[9]	Includes inter-refinery transfer volumes.
[10]	Includes the impact of Hess’ Retail Operations and Related Assets from the September 30, 2014 acquisition date.
[11]	The price paid by consumers less the cost of refined products, including transportation, consumer excise taxes and bankcard processing fees, divided by gasoline and distillate sales volume.
[12]	Excludes cigarettes.
[13]	On owned common-carrier pipelines, excluding equity method investments.
[14]	Includes the results of the MarkWest assets beginning on the Dec. 4, 2015 acquisition date.Includes amounts related to unconsolidated equity method investments on a 100% basis.