3.19.3.a.u2 html 832 713 1 true 219 0 false 11 false false R1.htm 0001000 - Document - Document and Entity Information Sheet http://www.marathonpetroleum.com/role/DocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 1001000 - Statement - Consolidated Statements of Income Sheet http://www.marathonpetroleum.com/role/ConsolidatedStatementsOfIncome Consolidated Statements of Income Statements 2 false false R3.htm 1001001 - Statement - Consolidated Statements of Income Consolidated Statements of Income (Parenthetical) Sheet http://www.marathonpetroleum.com/role/ConsolidatedStatementsOfIncomeConsolidatedStatementsOfIncomeParenthetical Consolidated Statements of Income Consolidated Statements of Income (Parenthetical) Statements 3 false false R4.htm 1002000 - Statement - Consolidated Statements of Comprehensive Income Statement Sheet http://www.marathonpetroleum.com/role/ConsolidatedStatementsOfComprehensiveIncomeStatement Consolidated Statements of Comprehensive Income Statement Statements 4 false false R5.htm 1003000 - Statement - Consolidated Balance Sheets Sheet http://www.marathonpetroleum.com/role/ConsolidatedBalanceSheets Consolidated Balance Sheets Statements 5 false false R6.htm 1003501 - Statement - Consolidated Balance Sheets (Parenthetical) Sheet http://www.marathonpetroleum.com/role/ConsolidatedBalanceSheetsParenthetical Consolidated Balance Sheets (Parenthetical) Statements 6 false false R7.htm 1004000 - Statement - Consolidated Statements of Cash Flows Sheet http://www.marathonpetroleum.com/role/ConsolidatedStatementsOfCashFlows Consolidated Statements of Cash Flows Statements 7 false false R8.htm 1005000 - Statement - Consolidated Statements of Equity Sheet http://www.marathonpetroleum.com/role/ConsolidatedStatementsOfEquity Consolidated Statements of Equity Statements 8 false false R9.htm 2101100 - Disclosure - Description of the Business and Basis of Presentation Sheet http://www.marathonpetroleum.com/role/DescriptionOfBusinessAndBasisOfPresentation Description of the Business and Basis of Presentation Notes 9 false false R10.htm 2103100 - Disclosure - Summary of Principal Accounting Policies Sheet http://www.marathonpetroleum.com/role/SummaryOfPrincipalAccountingPolicies Summary of Principal Accounting Policies Notes 10 false false R11.htm 2106100 - Disclosure - Accounting Standards Sheet http://www.marathonpetroleum.com/role/AccountingStandards Accounting Standards Notes 11 false false R12.htm 2107100 - Disclosure - Acquisitions Sheet http://www.marathonpetroleum.com/role/Acquisitions Acquisitions Notes 12 false false R13.htm 2109100 - Disclosure - Investments and Noncontrolling Interests Sheet http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterests Investments and Noncontrolling Interests Notes 13 false false R14.htm 2110100 - Disclosure - Related Party Agreements and Transactions Sheet http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactions Related Party Agreements and Transactions Notes 14 false false R15.htm 2111100 - Disclosure - Net Income (Loss) Per Limited Partner Unit Sheet http://www.marathonpetroleum.com/role/NetIncomeLossPerLimitedPartnerUnit Net Income (Loss) Per Limited Partner Unit Notes 15 false false R16.htm 2112100 - Disclosure - Equity Sheet http://www.marathonpetroleum.com/role/Equity Equity Notes 16 false false R17.htm 2113100 - Disclosure - Redeemable Preferred Units Sheet http://www.marathonpetroleum.com/role/RedeemablePreferredUnits Redeemable Preferred Units Notes 17 false false R18.htm 2114100 - Disclosure - Segment Information Sheet http://www.marathonpetroleum.com/role/SegmentInformation Segment Information Notes 18 false false R19.htm 2116100 - Disclosure - Major Customers and Concentration of Credit Risk Sheet http://www.marathonpetroleum.com/role/MajorCustomersAndConcentrationOfCreditRisk Major Customers and Concentration of Credit Risk Notes 19 false false R20.htm 2118100 - Disclosure - Inventories Sheet http://www.marathonpetroleum.com/role/Inventories Inventories Notes 20 false false R21.htm 2119100 - Disclosure - Property, Plant and Equipment Sheet http://www.marathonpetroleum.com/role/PropertyPlantAndEquipment Property, Plant and Equipment Notes 21 false false R22.htm 2120100 - Disclosure - Goodwill and Intangibles Sheet http://www.marathonpetroleum.com/role/GoodwillAndIntangibles Goodwill and Intangibles Notes 22 false false R23.htm 2121100 - Disclosure - Fair Value Measurements Sheet http://www.marathonpetroleum.com/role/FairValueMeasurements Fair Value Measurements Notes 23 false false R24.htm 2124100 - Disclosure - Derivative Financial Instruments Sheet http://www.marathonpetroleum.com/role/DerivativeFinancialInstruments Derivative Financial Instruments Notes 24 false false R25.htm 2125100 - Disclosure - Debt Sheet http://www.marathonpetroleum.com/role/Debt Debt Notes 25 false false R26.htm 2126100 - Disclosure - Revenue Revenue Sheet http://www.marathonpetroleum.com/role/RevenueRevenue Revenue Revenue Notes 26 false false R27.htm 2127100 - Disclosure - Supplemental Cash Flow Information Sheet http://www.marathonpetroleum.com/role/SupplementalCashFlowInformation Supplemental Cash Flow Information Notes 27 false false R28.htm 2128100 - Disclosure - Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income Sheet http://www.marathonpetroleum.com/role/AccumulatedOtherComprehensiveIncomeAccumulatedOtherComprehensiveIncome Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income Notes 28 false false R29.htm 2129100 - Disclosure - Equity-Based Compensation Sheet http://www.marathonpetroleum.com/role/EquityBasedCompensation Equity-Based Compensation Notes 29 false false R30.htm 2135100 - Disclosure - Commitments and Contingencies Sheet http://www.marathonpetroleum.com/role/CommitmentsAndContingencies Commitments and Contingencies Notes 30 false false R31.htm 2136100 - Disclosure - Select Quarterly Financial Data Sheet http://www.marathonpetroleum.com/role/SelectQuarterlyFinancialData Select Quarterly Financial Data Notes 31 false false R32.htm 2201201 - Disclosure - Description of the Business and Basis of Presentation (Policies) Sheet http://www.marathonpetroleum.com/role/DescriptionOfBusinessAndBasisOfPresentationPolicies Description of the Business and Basis of Presentation (Policies) Policies http://www.marathonpetroleum.com/role/SummaryOfPrincipalAccountingPolicies 32 false false R33.htm 2203201 - Disclosure - Summary of Principal Accounting Policies (Policies) Sheet http://www.marathonpetroleum.com/role/SummaryOfPrincipalAccountingPoliciesPolicies Summary of Principal Accounting Policies (Policies) Policies http://www.marathonpetroleum.com/role/SummaryOfPrincipalAccountingPolicies 33 false false R34.htm 2206201 - Disclosure - Accounting Standards New Accounting Pronouncements Not yet Adopted (Tables) Sheet http://www.marathonpetroleum.com/role/AccountingStandardsNewAccountingPronouncementsNotYetAdoptedTables Accounting Standards New Accounting Pronouncements Not yet Adopted (Tables) Tables 34 false false R35.htm 2307301 - Disclosure - Acquisitions (Tables) Sheet http://www.marathonpetroleum.com/role/AcquisitionsTables Acquisitions (Tables) Tables http://www.marathonpetroleum.com/role/Acquisitions 35 false false R36.htm 2309301 - Disclosure - Investments and Noncontrolling Interests (Tables) Sheet http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterestsTables Investments and Noncontrolling Interests (Tables) Tables http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterests 36 false false R37.htm 2310301 - Disclosure - Related Party Agreements and Transactions (Tables) Sheet http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsTables Related Party Agreements and Transactions (Tables) Tables http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactions 37 false false R38.htm 2311301 - Disclosure - Net Income (Loss) Per Limited Partner Unit (Tables) Sheet http://www.marathonpetroleum.com/role/NetIncomeLossPerLimitedPartnerUnitTables Net Income (Loss) Per Limited Partner Unit (Tables) Tables http://www.marathonpetroleum.com/role/NetIncomeLossPerLimitedPartnerUnit 38 false false R39.htm 2312301 - Disclosure - Equity (Tables) Sheet http://www.marathonpetroleum.com/role/EquityTables Equity (Tables) Tables http://www.marathonpetroleum.com/role/Equity 39 false false R40.htm 2313301 - Disclosure - Redeemable Preferred Units (Tables) Sheet http://www.marathonpetroleum.com/role/RedeemablePreferredUnitsTables Redeemable Preferred Units (Tables) Tables http://www.marathonpetroleum.com/role/RedeemablePreferredUnits 40 false false R41.htm 2314301 - Disclosure - Segment Information (Tables) Sheet http://www.marathonpetroleum.com/role/SegmentInformationTables Segment Information (Tables) Tables http://www.marathonpetroleum.com/role/SegmentInformation 41 false false R42.htm 2318301 - Disclosure - Inventories (Tables) Sheet http://www.marathonpetroleum.com/role/InventoriesTables Inventories (Tables) Tables http://www.marathonpetroleum.com/role/Inventories 42 false false R43.htm 2319301 - Disclosure - Property, Plant and Equipment (Tables) Sheet http://www.marathonpetroleum.com/role/PropertyPlantAndEquipmentTables Property, Plant and Equipment (Tables) Tables http://www.marathonpetroleum.com/role/PropertyPlantAndEquipment 43 false false R44.htm 2320301 - Disclosure - Goodwill and Intangibles (Tables) Sheet http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesTables Goodwill and Intangibles (Tables) Tables http://www.marathonpetroleum.com/role/GoodwillAndIntangibles 44 false false R45.htm 2321301 - Disclosure - Fair Value Measurements (Tables) Sheet http://www.marathonpetroleum.com/role/FairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://www.marathonpetroleum.com/role/FairValueMeasurements 45 false false R46.htm 2324301 - Disclosure - Derivative Financial Instruments (Tables) Sheet http://www.marathonpetroleum.com/role/DerivativeFinancialInstrumentsTables Derivative Financial Instruments (Tables) Tables http://www.marathonpetroleum.com/role/DerivativeFinancialInstruments 46 false false R47.htm 2325301 - Disclosure - Debt (Tables) Sheet http://www.marathonpetroleum.com/role/DebtTables Debt (Tables) Tables http://www.marathonpetroleum.com/role/Debt 47 false false R48.htm 2326301 - Disclosure - Revenue Revenue (Tables) Sheet http://www.marathonpetroleum.com/role/RevenueRevenueTables Revenue Revenue (Tables) Tables http://www.marathonpetroleum.com/role/RevenueRevenue 48 false false R49.htm 2327301 - Disclosure - Supplemental Cash Flow Information (Tables) Sheet http://www.marathonpetroleum.com/role/SupplementalCashFlowInformationTables Supplemental Cash Flow Information (Tables) Tables http://www.marathonpetroleum.com/role/SupplementalCashFlowInformation 49 false false R50.htm 2328301 - Disclosure - Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income (Tables) Sheet http://www.marathonpetroleum.com/role/AccumulatedOtherComprehensiveIncomeAccumulatedOtherComprehensiveIncomeTables Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income (Tables) Tables http://www.marathonpetroleum.com/role/AccumulatedOtherComprehensiveIncomeAccumulatedOtherComprehensiveIncome 50 false false R51.htm 2329301 - Disclosure - Equity-Based Compensation (Tables) Sheet http://www.marathonpetroleum.com/role/EquityBasedCompensationTables Equity-Based Compensation (Tables) Tables http://www.marathonpetroleum.com/role/EquityBasedCompensation 51 false false R52.htm 2333301 - Disclosure - Leases Lessee Disclosure (Tables) Sheet http://www.marathonpetroleum.com/role/LeasesLesseeDisclosureTables Leases Lessee Disclosure (Tables) Tables 52 false false R53.htm 2333302 - Disclosure - Leases Lessor Disclosures (Tables) Sheet http://www.marathonpetroleum.com/role/LeasesLessorDisclosuresTables Leases Lessor Disclosures (Tables) Tables 53 false false R54.htm 2335301 - Disclosure - Commitments and Contingencies (Tables) Sheet http://www.marathonpetroleum.com/role/CommitmentsAndContingenciesTables Commitments and Contingencies (Tables) Tables http://www.marathonpetroleum.com/role/CommitmentsAndContingencies 54 false false R55.htm 2336301 - Disclosure - Select Quarterly Financial Data (Tables) Sheet http://www.marathonpetroleum.com/role/SelectQuarterlyFinancialDataTables Select Quarterly Financial Data (Tables) Tables http://www.marathonpetroleum.com/role/SelectQuarterlyFinancialData 55 false false R56.htm 2401402 - Disclosure - Description of the Business and Basis of Presentation (Detail) Sheet http://www.marathonpetroleum.com/role/DescriptionOfBusinessAndBasisOfPresentationDetail Description of the Business and Basis of Presentation (Detail) Details http://www.marathonpetroleum.com/role/DescriptionOfBusinessAndBasisOfPresentationPolicies 56 false false R57.htm 2403402 - Disclosure - Summary of Principal Accounting Policies (Details) Sheet http://www.marathonpetroleum.com/role/SummaryOfPrincipalAccountingPoliciesDetails Summary of Principal Accounting Policies (Details) Details http://www.marathonpetroleum.com/role/SummaryOfPrincipalAccountingPoliciesPolicies 57 false false R58.htm 2406402 - Disclosure - Accounting Standards ASU 2016-02 Leases and related updates (Details) Sheet http://www.marathonpetroleum.com/role/AccountingStandardsAsu201602LeasesAndRelatedUpdatesDetails Accounting Standards ASU 2016-02 Leases and related updates (Details) Details 58 false false R59.htm 2407402 - Disclosure - Acquisitions Acquisitions (Andeavor Logistics LP) (Details) Sheet http://www.marathonpetroleum.com/role/AcquisitionsAcquisitionsAndeavorLogisticsLpDetails Acquisitions Acquisitions (Andeavor Logistics LP) (Details) Details 59 false false R60.htm 2407403 - Disclosure - Acquisitions Acquisitions (Acquisition Mt. Airy Terminal) (Details) Sheet http://www.marathonpetroleum.com/role/AcquisitionsAcquisitionsAcquisitionMtAiryTerminalDetails Acquisitions Acquisitions (Acquisition Mt. Airy Terminal) (Details) Details 60 false false R61.htm 2407404 - Disclosure - Acquisitions Acquisitions (Refining Logistics and Fuels Distribution) (Details) Sheet http://www.marathonpetroleum.com/role/AcquisitionsAcquisitionsRefiningLogisticsAndFuelsDistributionDetails Acquisitions Acquisitions (Refining Logistics and Fuels Distribution) (Details) Details 61 false false R62.htm 2407405 - Disclosure - Acquisitions (Joint-Interest Acquisition) (Details) Sheet http://www.marathonpetroleum.com/role/AcquisitionsJointInterestAcquisitionDetails Acquisitions (Joint-Interest Acquisition) (Details) Details http://www.marathonpetroleum.com/role/AcquisitionsTables 62 false false R63.htm 2407406 - Disclosure - Acquisitions (Acquisition of HST, WHC & MPLXT) (Details) Sheet http://www.marathonpetroleum.com/role/AcquisitionsAcquisitionOfHstWhcMplxtDetails Acquisitions (Acquisition of HST, WHC & MPLXT) (Details) Details http://www.marathonpetroleum.com/role/AcquisitionsTables 63 false false R64.htm 2407407 - Disclosure - Acquisitions (Acquisition of Ozark Pipeline) (Details) Sheet http://www.marathonpetroleum.com/role/AcquisitionsAcquisitionOfOzarkPipelineDetails Acquisitions (Acquisition of Ozark Pipeline) (Details) Details http://www.marathonpetroleum.com/role/AcquisitionsTables 64 false false R65.htm 2407408 - Disclosure - Acquisitions (Acquisition of MarEn Bakken) (Details) Sheet http://www.marathonpetroleum.com/role/AcquisitionsAcquisitionOfMarenBakkenDetails Acquisitions (Acquisition of MarEn Bakken) (Details) Details http://www.marathonpetroleum.com/role/AcquisitionsTables 65 false false R66.htm 2409402 - Disclosure - Investments and Noncontrolling Interest (Equity Method Investments) (Details) Sheet http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterestEquityMethodInvestmentsDetails Investments and Noncontrolling Interest (Equity Method Investments) (Details) Details http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterestsTables 66 false false R67.htm 2409403 - Disclosure - Investments and Noncontrolling Interests (Summary of Equity Method Investment Financial Information) (Details) Sheet http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterestsSummaryOfEquityMethodInvestmentFinancialInformationDetails Investments and Noncontrolling Interests (Summary of Equity Method Investment Financial Information) (Details) Details http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterestsTables 67 false false R68.htm 2409404 - Disclosure - Investments and Noncontrolling Interests (Narrative) (Details) Sheet http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterestsNarrativeDetails Investments and Noncontrolling Interests (Narrative) (Details) Details http://www.marathonpetroleum.com/role/InvestmentsAndNoncontrollingInterestsTables 68 false false R69.htm 2410402 - Disclosure - Related Party Agreements and Transactions (Narrative) (Detail) Sheet http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsNarrativeDetail Related Party Agreements and Transactions (Narrative) (Detail) Details http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsTables 69 false false R70.htm 2410403 - Disclosure - Related Party Agreements and Transactions (Intercompany Loans with Related Parties) (Detail) Sheet http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsIntercompanyLoansWithRelatedPartiesDetail Related Party Agreements and Transactions (Intercompany Loans with Related Parties) (Detail) Details http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsTables 70 false false R71.htm 2410404 - Disclosure - Related Party Agreements and Transactions (Summary of Revenue by Income Statement RP Line Item) (Detail) Sheet http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsSummaryOfRevenueByIncomeStatementRpLineItemDetail Related Party Agreements and Transactions (Summary of Revenue by Income Statement RP Line Item) (Detail) Details http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsTables 71 false false R72.htm 2410405 - Disclosure - Related Party Agreements and Transactions (Summary of Expenses by Income Statement RP Line Item) (Detail) Sheet http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsSummaryOfExpensesByIncomeStatementRpLineItemDetail Related Party Agreements and Transactions (Summary of Expenses by Income Statement RP Line Item) (Detail) Details http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsTables 72 false false R73.htm 2410406 - Disclosure - Related Party Agreements and Transactions (Summary of Balance Sheet by RP Line Item) (Details) Sheet http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsSummaryOfBalanceSheetByRpLineItemDetails Related Party Agreements and Transactions (Summary of Balance Sheet by RP Line Item) (Details) Details http://www.marathonpetroleum.com/role/RelatedPartyAgreementsAndTransactionsTables 73 false false R74.htm 2411402 - Disclosure - Net Income (Loss) Per Limited Partner Unit (Schedule of Distributions by Partner Class) (Detail) Sheet http://www.marathonpetroleum.com/role/NetIncomeLossPerLimitedPartnerUnitScheduleOfDistributionsByPartnerClassDetail Net Income (Loss) Per Limited Partner Unit (Schedule of Distributions by Partner Class) (Detail) Details http://www.marathonpetroleum.com/role/NetIncomeLossPerLimitedPartnerUnitTables 74 false false R75.htm 2411403 - Disclosure - Net Income (Loss) Per Limited Partner Unit (Basic and Diluted Earnings Per Unit) (Detail) Sheet http://www.marathonpetroleum.com/role/NetIncomeLossPerLimitedPartnerUnitBasicAndDilutedEarningsPerUnitDetail Net Income (Loss) Per Limited Partner Unit (Basic and Diluted Earnings Per Unit) (Detail) Details http://www.marathonpetroleum.com/role/NetIncomeLossPerLimitedPartnerUnitTables 75 false false R76.htm 2412402 - Disclosure - Equity (Units Outstanding) (Details) Sheet http://www.marathonpetroleum.com/role/EquityUnitsOutstandingDetails Equity (Units Outstanding) (Details) Details http://www.marathonpetroleum.com/role/EquityTables 76 false false R77.htm 2412403 - Disclosure - Equity (Reorganization Transactions) (Details) Sheet http://www.marathonpetroleum.com/role/EquityReorganizationTransactionsDetails Equity (Reorganization Transactions) (Details) Details http://www.marathonpetroleum.com/role/EquityTables 77 false false R78.htm 2412404 - Disclosure - Equity (ATM Program) (Details) Sheet http://www.marathonpetroleum.com/role/EquityAtmProgramDetails Equity (ATM Program) (Details) Details http://www.marathonpetroleum.com/role/EquityTables 78 false false R79.htm 2412405 - Disclosure - Equity (Changes in Partners Capital, Unit Rollforward) (Details) Sheet http://www.marathonpetroleum.com/role/EquityChangesInPartnersCapitalUnitRollforwardDetails Equity (Changes in Partners Capital, Unit Rollforward) (Details) Details http://www.marathonpetroleum.com/role/EquityTables 79 false false R80.htm 2412406 - Disclosure - Equity (Net Income Allocation) (Details) Sheet http://www.marathonpetroleum.com/role/EquityNetIncomeAllocationDetails Equity (Net Income Allocation) (Details) Details http://www.marathonpetroleum.com/role/EquityTables 80 false false R81.htm 2412407 - Disclosure - Equity (Cash Distributions) (Details) Sheet http://www.marathonpetroleum.com/role/EquityCashDistributionsDetails Equity (Cash Distributions) (Details) Details http://www.marathonpetroleum.com/role/EquityTables 81 false false R82.htm 2412408 - Disclosure - Equity (Cash Distributions Applicable to Period the Distributions Were Earned) (Details) Sheet http://www.marathonpetroleum.com/role/EquityCashDistributionsApplicableToPeriodDistributionsWereEarnedDetails Equity (Cash Distributions Applicable to Period the Distributions Were Earned) (Details) Details http://www.marathonpetroleum.com/role/EquityTables 82 false false R83.htm 2413402 - Disclosure - Redeemable Preferred Units (Narrative) (Details) Sheet http://www.marathonpetroleum.com/role/RedeemablePreferredUnitsNarrativeDetails Redeemable Preferred Units (Narrative) (Details) Details http://www.marathonpetroleum.com/role/RedeemablePreferredUnitsTables 83 false false R84.htm 2413403 - Disclosure - Redeemable Preferred Units (Rollforward of Redeemable Preferred Units) (Details) Sheet http://www.marathonpetroleum.com/role/RedeemablePreferredUnitsRollforwardOfRedeemablePreferredUnitsDetails Redeemable Preferred Units (Rollforward of Redeemable Preferred Units) (Details) Details http://www.marathonpetroleum.com/role/RedeemablePreferredUnitsTables 84 false false R85.htm 2414402 - Disclosure - Segment Information (Details) Sheet http://www.marathonpetroleum.com/role/SegmentInformationDetails Segment Information (Details) Details http://www.marathonpetroleum.com/role/SegmentInformationTables 85 false false R86.htm 2414403 - Disclosure - Segment Information - Revenues and Adjusted EBITDA (Details) Sheet http://www.marathonpetroleum.com/role/SegmentInformationRevenuesAndAdjustedEbitdaDetails Segment Information - Revenues and Adjusted EBITDA (Details) Details 86 false false R87.htm 2414404 - Disclosure - Segment Information - Assets by Segment (Details) Sheet http://www.marathonpetroleum.com/role/SegmentInformationAssetsBySegmentDetails Segment Information - Assets by Segment (Details) Details 87 false false R88.htm 2414405 - Disclosure - Segment Information - Reconciliation Adjusted EBITDA to Net income (Details) Sheet http://www.marathonpetroleum.com/role/SegmentInformationReconciliationAdjustedEbitdaToNetIncomeDetails Segment Information - Reconciliation Adjusted EBITDA to Net income (Details) Details 88 false false R89.htm 2416401 - Disclosure - Major Customers and Concentration of Credit Risk (Details) Sheet http://www.marathonpetroleum.com/role/MajorCustomersAndConcentrationOfCreditRiskDetails Major Customers and Concentration of Credit Risk (Details) Details http://www.marathonpetroleum.com/role/MajorCustomersAndConcentrationOfCreditRisk 89 false false R90.htm 2418402 - Disclosure - Inventories (Summary of Inventories) (Details) Sheet http://www.marathonpetroleum.com/role/InventoriesSummaryOfInventoriesDetails Inventories (Summary of Inventories) (Details) Details http://www.marathonpetroleum.com/role/InventoriesTables 90 false false R91.htm 2419402 - Disclosure - Property, Plant and Equipment (Summary of Property, Plant and Equipment) (Detail) Sheet http://www.marathonpetroleum.com/role/PropertyPlantAndEquipmentSummaryOfPropertyPlantAndEquipmentDetail Property, Plant and Equipment (Summary of Property, Plant and Equipment) (Detail) Details http://www.marathonpetroleum.com/role/PropertyPlantAndEquipmentTables 91 false false R92.htm 2419403 - Disclosure - Property Plant and Equipment (Narrative) (Details) Sheet http://www.marathonpetroleum.com/role/PropertyPlantAndEquipmentNarrativeDetails Property Plant and Equipment (Narrative) (Details) Details 92 false false R93.htm 2420402 - Disclosure - Goodwill and Intangibles (Goodwill) (Narrative) (Details) Sheet http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesGoodwillNarrativeDetails Goodwill and Intangibles (Goodwill) (Narrative) (Details) Details http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesTables 93 false false R94.htm 2420403 - Disclosure - Goodwill and Intangibles (Reconciliation of Goodwill) (Details) Sheet http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesReconciliationOfGoodwillDetails Goodwill and Intangibles (Reconciliation of Goodwill) (Details) Details http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesTables 94 false false R95.htm 2420404 - Disclosure - Goodwill and Intangibles (Intangible Assets) (Details) Sheet http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesIntangibleAssetsDetails Goodwill and Intangibles (Intangible Assets) (Details) Details http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesTables 95 false false R96.htm 2420405 - Disclosure - Goodwill and Intangibles (Future Amortization Expense) (Details) Sheet http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesFutureAmortizationExpenseDetails Goodwill and Intangibles (Future Amortization Expense) (Details) Details http://www.marathonpetroleum.com/role/GoodwillAndIntangiblesTables 96 false false R97.htm 2421402 - Disclosure - Fair Value Measurements - Recurring (Financial Instruments by Valuation Hierarchy) (Details) Sheet http://www.marathonpetroleum.com/role/FairValueMeasurementsRecurringFinancialInstrumentsByValuationHierarchyDetails Fair Value Measurements - Recurring (Financial Instruments by Valuation Hierarchy) (Details) Details 97 false false R98.htm 2421403 - Disclosure - Fair Value Measurements - Recurring (Significant Unobservable Inputs in Level 3 Valuation) (Details) Sheet http://www.marathonpetroleum.com/role/FairValueMeasurementsRecurringSignificantUnobservableInputsInLevel3ValuationDetails Fair Value Measurements - Recurring (Significant Unobservable Inputs in Level 3 Valuation) (Details) Details 98 false false R99.htm 2421404 - Disclosure - Fair Value Measurements - Recurring (Changes in Level 3 Measurements) (Details) Sheet http://www.marathonpetroleum.com/role/FairValueMeasurementsRecurringChangesInLevel3MeasurementsDetails Fair Value Measurements - Recurring (Changes in Level 3 Measurements) (Details) Details 99 false false R100.htm 2421405 - Disclosure - Fair Value Measurements - Reported (Details) Sheet http://www.marathonpetroleum.com/role/FairValueMeasurementsReportedDetails Fair Value Measurements - Reported (Details) Details 100 false false R101.htm 2424403 - Disclosure - Derivative Financial Instruments (Embedded Derivatives in Commodity Contracts) (Details) Sheet http://www.marathonpetroleum.com/role/DerivativeFinancialInstrumentsEmbeddedDerivativesInCommodityContractsDetails Derivative Financial Instruments (Embedded Derivatives in Commodity Contracts) (Details) Details http://www.marathonpetroleum.com/role/DerivativeFinancialInstrumentsTables 101 false false R102.htm 2424404 - Disclosure - Derivative Financial Instruments (Derivatives Balance Sheet Location) (Details) Sheet http://www.marathonpetroleum.com/role/DerivativeFinancialInstrumentsDerivativesBalanceSheetLocationDetails Derivative Financial Instruments (Derivatives Balance Sheet Location) (Details) Details http://www.marathonpetroleum.com/role/DerivativeFinancialInstrumentsTables 102 false false R103.htm 2424405 - Disclosure - Derivative Financial Instruments (Derivatives Income Statement Location) (Details) Sheet http://www.marathonpetroleum.com/role/DerivativeFinancialInstrumentsDerivativesIncomeStatementLocationDetails Derivative Financial Instruments (Derivatives Income Statement Location) (Details) Details http://www.marathonpetroleum.com/role/DerivativeFinancialInstrumentsTables 103 false false R104.htm 2425402 - Disclosure - Debt (Summary of Outstanding Borrowings) (Details) Sheet http://www.marathonpetroleum.com/role/DebtSummaryOfOutstandingBorrowingsDetails Debt (Summary of Outstanding Borrowings) (Details) Details http://www.marathonpetroleum.com/role/DebtTables 104 false false R105.htm 2425403 - Disclosure - Debt (Summary of Outstanding Borrowings Interest Rates and Table Due Dates) (Details) Sheet http://www.marathonpetroleum.com/role/DebtSummaryOfOutstandingBorrowingsInterestRatesAndTableDueDatesDetails Debt (Summary of Outstanding Borrowings Interest Rates and Table Due Dates) (Details) Details http://www.marathonpetroleum.com/role/DebtTables 105 false false R106.htm 2425404 - Disclosure - Debt (Schedule of Debt Payments) (Detail) Sheet http://www.marathonpetroleum.com/role/DebtScheduleOfDebtPaymentsDetail Debt (Schedule of Debt Payments) (Detail) Details http://www.marathonpetroleum.com/role/DebtTables 106 false false R107.htm 2425405 - Disclosure - Debt (Credit Agreements) (Detail) Sheet http://www.marathonpetroleum.com/role/DebtCreditAgreementsDetail Debt (Credit Agreements) (Detail) Details http://www.marathonpetroleum.com/role/DebtTables 107 false false R108.htm 2425406 - Disclosure - Debt (Senior Notes) (Details) Notes http://www.marathonpetroleum.com/role/DebtSeniorNotesDetails Debt (Senior Notes) (Details) Details http://www.marathonpetroleum.com/role/DebtTables 108 false false R109.htm 2425407 - Disclosure - Debt (SMR Transaction) (Details) Sheet http://www.marathonpetroleum.com/role/DebtSmrTransactionDetails Debt (SMR Transaction) (Details) Details http://www.marathonpetroleum.com/role/DebtTables 109 false false R110.htm 2426402 - Disclosure - Revenue Disaggregation of Revenue (Details) Sheet http://www.marathonpetroleum.com/role/RevenueDisaggregationOfRevenueDetails Revenue Disaggregation of Revenue (Details) Details 110 false false R111.htm 2426403 - Disclosure - Revenue Contract Balance Rollforward (Details) Sheet http://www.marathonpetroleum.com/role/RevenueContractBalanceRollforwardDetails Revenue Contract Balance Rollforward (Details) Details 111 false false R112.htm 2426404 - Disclosure - Revenue Remaining Performance Obligations (Details) Sheet http://www.marathonpetroleum.com/role/RevenueRemainingPerformanceObligationsDetails Revenue Remaining Performance Obligations (Details) Details 112 false false R113.htm 2427402 - Disclosure - Supplemental Cash Flow Information (Summary of Supplemental Cash Flow Information) (Details) Sheet http://www.marathonpetroleum.com/role/SupplementalCashFlowInformationSummaryOfSupplementalCashFlowInformationDetails Supplemental Cash Flow Information (Summary of Supplemental Cash Flow Information) (Details) Details http://www.marathonpetroleum.com/role/SupplementalCashFlowInformationTables 113 false false R114.htm 2427403 - Disclosure - Supplemental Cash Flow Information Supplemental Cash Flow Information (Details) Sheet http://www.marathonpetroleum.com/role/SupplementalCashFlowInformationSupplementalCashFlowInformationDetails Supplemental Cash Flow Information Supplemental Cash Flow Information (Details) Details 114 false false R115.htm 2427404 - Disclosure - Supplemental Cash Flow Information (Summary of Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures) (Detail) Sheet http://www.marathonpetroleum.com/role/SupplementalCashFlowInformationSummaryOfReconciliationOfAdditionsToPropertyPlantAndEquipmentToTotalCapitalExpendituresDetail Supplemental Cash Flow Information (Summary of Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures) (Detail) Details http://www.marathonpetroleum.com/role/SupplementalCashFlowInformationTables 115 false false R116.htm 2428402 - Disclosure - Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income (Details) Sheet http://www.marathonpetroleum.com/role/AccumulatedOtherComprehensiveIncomeAccumulatedOtherComprehensiveIncomeDetails Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income (Details) Details http://www.marathonpetroleum.com/role/AccumulatedOtherComprehensiveIncomeAccumulatedOtherComprehensiveIncomeTables 116 false false R117.htm 2429402 - Disclosure - Equity-Based Compensation (Narrative) (Detail) Sheet http://www.marathonpetroleum.com/role/EquityBasedCompensationNarrativeDetail Equity-Based Compensation (Narrative) (Detail) Details http://www.marathonpetroleum.com/role/EquityBasedCompensationTables 117 false false R118.htm 2429403 - Disclosure - Equity-Based Compensation (Summary of Phantom Unit Award Activity) (Detail) Sheet http://www.marathonpetroleum.com/role/EquityBasedCompensationSummaryOfPhantomUnitAwardActivityDetail Equity-Based Compensation (Summary of Phantom Unit Award Activity) (Detail) Details http://www.marathonpetroleum.com/role/EquityBasedCompensationTables 118 false false R119.htm 2429404 - Disclosure - Equity-Based Compensation (Summary of Values Related To Vested and Unvested Restricted Stock Awards) (Details) Sheet http://www.marathonpetroleum.com/role/EquityBasedCompensationSummaryOfValuesRelatedToVestedAndUnvestedRestrictedStockAwardsDetails Equity-Based Compensation (Summary of Values Related To Vested and Unvested Restricted Stock Awards) (Details) Details http://www.marathonpetroleum.com/role/EquityBasedCompensationTables 119 false false R120.htm 2429405 - Disclosure - Equity-Based Compensation (Summary of Performance Unit Award Activity) (Details) Sheet http://www.marathonpetroleum.com/role/EquityBasedCompensationSummaryOfPerformanceUnitAwardActivityDetails Equity-Based Compensation (Summary of Performance Unit Award Activity) (Details) Details http://www.marathonpetroleum.com/role/EquityBasedCompensationTables 120 false false R121.htm 2429406 - Disclosure - Equity-Based Compensation (Assumptions) (Details) Sheet http://www.marathonpetroleum.com/role/EquityBasedCompensationAssumptionsDetails Equity-Based Compensation (Assumptions) (Details) Details http://www.marathonpetroleum.com/role/EquityBasedCompensationTables 121 false false R122.htm 2433404 - Disclosure - Leases Lessee Disclosures (Details) Sheet http://www.marathonpetroleum.com/role/LeasesLesseeDisclosuresDetails Leases Lessee Disclosures (Details) Details http://www.marathonpetroleum.com/role/LeasesLesseeDisclosureTables 122 false false R123.htm 2433405 - Disclosure - Leases Lessor Disclosures (Details) Sheet http://www.marathonpetroleum.com/role/LeasesLessorDisclosuresDetails Leases Lessor Disclosures (Details) Details http://www.marathonpetroleum.com/role/LeasesLessorDisclosuresTables 123 false false R124.htm 2435402 - Disclosure - Commitments and Contingencies (Detail) Sheet http://www.marathonpetroleum.com/role/CommitmentsAndContingenciesDetail Commitments and Contingencies (Detail) Details http://www.marathonpetroleum.com/role/CommitmentsAndContingenciesTables 124 false false R125.htm 2435403 - Disclosure - Commitments and Contingencies (Minimum Future Payments) (Details) Sheet http://www.marathonpetroleum.com/role/CommitmentsAndContingenciesMinimumFuturePaymentsDetails Commitments and Contingencies (Minimum Future Payments) (Details) Details http://www.marathonpetroleum.com/role/CommitmentsAndContingenciesTables 125 false false R126.htm 2435404 - Disclosure - Commitments and Contingencies (SMR Liability) (Details) Sheet http://www.marathonpetroleum.com/role/CommitmentsAndContingenciesSmrLiabilityDetails Commitments and Contingencies (SMR Liability) (Details) Details http://www.marathonpetroleum.com/role/CommitmentsAndContingenciesTables 126 false false R127.htm 2436402 - Disclosure - Select Quarterly Financial Data (Detail) Sheet http://www.marathonpetroleum.com/role/SelectQuarterlyFinancialDataDetail Select Quarterly Financial Data (Detail) Details http://www.marathonpetroleum.com/role/SelectQuarterlyFinancialDataTables 127 false false All Reports Book All Reports mplx-20191231x10k.htm mpc-20191231.xsd mpc-20191231_cal.xml mpc-20191231_def.xml mpc-20191231_lab.xml mpc-20191231_pre.xml mplx-20191231xex10102.htm mplx-20191231xex10103.htm mplx-20191231xex1075.htm mplx-20191231xex211.htm mplx-20191231xex231.htm mplx-20191231xex241.htm mplx-20191231xex311.htm mplx-20191231xex312.htm mplx-20191231xex321.htm mplx-20191231xex322.htm mplx-20191231xex433.htm businesssegmentresults.jpg fractionatedthroughput.jpg gatheringthroughput.jpg gpflowdiagram.jpg gpincomefromops.jpg gprevenue.jpg gpsegmentadjebitda.jpg lsflowdiagram.jpg lsincomefromops.jpg lsrevenue.jpg lssegmentadjebitda.jpg mdafinancialhighlights.jpg mplxorgchart2019.jpg pipelinethroughput.jpg processingthroughput.jpg updatedmplxoperationsmap.jpg http://fasb.org/us-gaap/2019-01-31 http://xbrl.sec.gov/dei/2019-01-31 http://fasb.org/srt/2019-01-31 true true