Pipeline Barrels Handled

No definition available.

Name:	mpc_PipelineBarrelsHandled
Namespace Prefix:	mpc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Pipeline diameter

+ References

No definition available.

+ Details

Name:	mpc_Pipelinediameter
Namespace Prefix:	mpc_
Data Type:	num:lengthItemType
Balance Type:	na
Period Type:	duration

- Definition

Pipeline length

+ References

No definition available.

+ Details

Name:	mpc_Pipelinelength
Namespace Prefix:	mpc_
Data Type:	num:lengthItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

+ Details

Name:	us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=mpc_OzarkPipelineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Acquisitions (Acquisition of Ozark Pipeline) (Details) bbl / d in Thousands, $ in Millions		10 Months Ended	12 Months Ended
	Mar. 01, 2017 USD ($) bbl / d in mi	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Payments to acquire property, plant, and equipment			$ 1,411	$ 1,313	$ 334
Ozark Pipeline
Business Acquisition [Line Items]
Payments to acquire property, plant, and equipment	$ 219
Pipeline length \| mi	433
Pipeline diameter \| in	22
Pipeline barrels handled \| bbl / d	230
Revenues and other income		$ 64
Income from operations		$ 20