MPLX (MPLX) 10-K 27 Feb 25 2024 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2024	Feb. 21, 2025	Jun. 30, 2024
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-35714
Entity Registrant Name	MPLX LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-0005456
Entity Address, Address Line One	200 E. Hardin Street
Entity Address, City or Town	Findlay
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	45840-3229
City Area Code	419
Local Phone Number	422-2121
Title of 12(b) Security	Common Units Representing Limited Partnership Interests
Trading Symbol	MPLX
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 15.9
Entity Common Stock, Shares Outstanding		1,022,509,781
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Entity Central Index Key	0001552000
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2024
Document Information [Line Items]
Document Transition Report	false
Document Financial Statement Error Correction [Flag]	false

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2024
Auditor Information [Abstract]
Auditor Firm ID	238
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Toledo, Ohio

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues and other income:
Sales-type lease revenue		$ 136	$ 136	$ 62
Sales-type lease revenue, related parties		475	500	465
Income from equity method investments		802	600	476
Total revenues and other income		11,933	11,281	11,613
Costs and expenses:
Purchases - related parties		1,583	1,544	1,413
Depreciation and amortization		1,283	1,213	1,230
General and administrative expenses		427	379	335
Other taxes		131	131	115
Total costs and expenses		6,645	6,381	6,702
Income from operations		5,288	4,900	4,911
Net interest and other financial costs		921	923	925
Income before income taxes		4,367	3,977	3,986
Provision for income taxes		10	11	8
Net income		4,357	3,966	3,978
Less: Net income attributable to noncontrolling interests		40	38	34
Limited partners’ interest in net income attributable to MPLX LP		$ 4,290	$ 3,829	$ 3,815
Net income attributable to MPLX LP per limited partner unit:
Common - basic		$ 4.21	$ 3.80	$ 3.75
Common - diluted		$ 4.21	$ 3.80	$ 3.75
Weighted average limited partner units outstanding:
Common - basic		1,016	1,001	1,010
Common - diluted		1,017	1,002	1,010
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	[1]	$ 4,317	$ 3,928	$ 3,944
Nonrelated Party
Revenues and other income:
Rental Income		251	243	327
Sales-type lease revenue		136	136	62
Other Income		70	126	485
Costs and expenses:
Rental cost of sales		82	82	123
Related Party
Revenues and other income:
Rental Income		853	822	763
Sales-type lease revenue, related parties		475	500	465
Other Income		157	121	111
Costs and expenses:
Rental cost of sales		18	33	54
Service [Member]
Revenues and other income:
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties		2,770	2,539	2,359
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties		4,180	3,985	3,754
Product [Member]
Revenues and other income:
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties		1,657	1,665	2,219
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties		225	250	198
Oil and Gas, Refining and Marketing [Member]
Costs and expenses:
Cost of revenues (excludes items below)		1,560	1,401	1,369
Natural Gas, Midstream [Member]
Costs and expenses:
Purchased product costs		1,561	1,598	2,063
Service, Other [Member]
Revenues and other income:
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties		357	294	394
Series A Preferred Stock [Member]
Costs and expenses:
Dividends, Preferred Stock		27	94	88
Series B Preferred Stock [Member]
Costs and expenses:
Dividends, Preferred Stock		$ 0	$ 5	$ 41
[1]Allocation of net income attributable to MPLX LP assumes all earnings for the period have been distributed based on the distribution priorities applicable to the period.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 4,357	$ 3,966	$ 3,978
Other comprehensive income, net of tax:
Remeasurements of pension and other postretirement benefits related to equity method investments, net of tax	1	4	9
Comprehensive income	4,358	3,970	3,987
Less comprehensive income attributable to:
Noncontrolling interests	40	38	34
Comprehensive income attributable to MPLX LP	$ 4,318	$ 3,932	$ 3,953

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Assets, Current [Abstract]
Cash and cash equivalents	$ 1,519	$ 1,048
Receivables, net	718	823
Inventories	180	159
Other current assets	29	30
Total current assets	3,276	2,808
Equity method investments	4,531	3,743
Property, plant and equipment, net	19,154	19,264
Intangibles, net	518	654
Goodwill	7,645	7,645
Right of use assets, net	273	264
Other noncurrent assets	994	990
Total assets	37,511	36,529
Liabilities, Current [Abstract]
Accounts payable	147	153
Accrued liabilities	295	300
Accrued property, plant and equipment	208	216
Long-term debt due within one year	1,693	1,135
Accrued interest payable	244	242
Total current liabilities	3,235	2,624
Long-term deferred revenue	317	347
Long-term debt	19,255	19,296
Deferred income taxes	18	16
Long-term operating lease liabilities	217	211
Total liabilities	23,501	22,945
Commitments and contingencies (see Note 22)
Series A Preferred Units	203	895
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Accumulated other comprehensive loss	(3)	(4)
Total MPLX LP partners’ capital	13,576	12,454
Noncontrolling interests	231	235
Total equity	13,807	12,689
Total liabilities, preferred units and equity	37,511	36,529
Related Party
Assets, Current [Abstract]
Receivables, net	620	587
Current assets - related parties	830	748
Other current assets	1	7
Right of use assets, net	226	227
Noncurrent assets - related parties	1,120	1,161
Liabilities, Current [Abstract]
Operating lease liabilities	2	1
Other Liabilities, Current	396	360
Long-term deferred revenue	110	99
Other Long-term Liabilities	334	325
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Limited Partners' Capital Account	4,257	3,758
Nonrelated Party
Assets, Current [Abstract]
Right of use assets, net	273	264
Liabilities, Current [Abstract]
Operating lease liabilities	45	45
Other Liabilities, Current	207	173
Long-term deferred revenue	315	344
Other Long-term Liabilities	125	126
Long-term operating lease liabilities	217	211
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Limited Partners' Capital Account	$ 9,322	$ 8,700

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Dec. 31, 2024	Dec. 31, 2023
Units outstanding	1,017,142,290	1,003,498,875
Series A Preferred Stock [Member]
Series A preferred, Units Outstanding	6,000,000	27,000,000
Nonrelated Party | Common Unit-holders Public
Units outstanding	370,000,000	356,000,000
Related Party
Units outstanding	647,415,452
Related Party | Common Unit-holders Public
Units outstanding	647,000,000	647,000,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities:
Net income		$ 4,357	$ 3,966	$ 3,978
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred financing costs		54	55	73
Depreciation and amortization		1,283	1,213	1,230
Deferred income taxes		2	3	3
Gain on sales-type leases and equity method investments		(20)	(92)	(509)
Loss/(gain) on disposal of assets		3	(14)	34
Income from equity method investments		(802)	(600)	(476)
Distributions from unconsolidated affiliates		826	736	578
Change in fair value of derivatives		(3)	0	(47)
Changes in:
Receivables		180	14	14
Inventories		(20)	(19)	(5)
Current accounts payable and other current assets and liabilities		5	(17)	(26)
Assets and liabilities - related parties		84	84	40
Right of use assets and operating lease liabilities		(3)	0	(3)
Deferred revenue		(5)	107	108
All other, net		5	(39)	27
Net cash provided by operating activities		5,946	5,397	5,019
Investing activities:
Additions to property, plant and equipment		(1,056)	(937)	(806)
Acquisitions, net of cash acquired		(622)	(246)	(28)
Disposal of assets		1	26	84
Investments - acquisitions and contributions		464	98	217
Investments - redemptions, repayments, return of capital and sales proceeds		146	3	11
Net cash used in investing activities		(1,995)	(1,252)	(956)
Financing activities:
Long-term debt borrowings		1,630	1,589	3,379
Long-term debt repayments		1,151	1,001	2,202
Debt issuance costs		(15)	(15)	(29)
Unit repurchases	[1]	(326)	0	(491)
Distributions to noncontrolling interests		(44)	(41)	(38)
Distributions to LP unitholders		(3,559)	(3,181)	(2,921)
Contributions from MPC		35	31	44
All other, net		(6)	(2)	(4)
Net cash used in financing activities		(3,480)	(3,335)	(3,838)
Net change in cash, cash equivalents and restricted cash		471	810	225
Cash, cash equivalents and restricted cash at beginning of period		1,048	238	13
Cash, cash equivalents and restricted cash at end of period		1,519	1,048	238
Revolving Credit Facility
Financing activities:
Related party debt borrowings		0	0	2,989
Related party debt repayments		0	0	(4,439)
Series A Preferred Stock [Member]
Financing activities:
Distributions to Preferred Unitholders		(44)	(94)	(85)
Series B Preferred Stock [Member]
Financing activities:
Redemption of Series B preferred units		0	(600)	0
Distributions to Preferred Unitholders		$ 0	$ (21)	$ (41)
[1] Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.

Consolidated Statements of Equi

Consolidated Statements of Equity and Series A Preferred Units (Consolidated Statements of Equity) - USD ($) $ in Millions	Total	Common Unit-holders Public	Common Unit-holder MPC	Series B Preferred Unit-holders	Accumulated Other Comprehensive Loss	Non-controlling Interests
Beginning Balance at Dec. 31, 2021	$ 12,052	$ 8,579	$ 2,638	$ 611	$ (17)	$ 241
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,890	1,371	2,444	41	0	34
Unit repurchases	(491)	(491)	0	0	0	0
Distributions	(3,000)	(1,050)	(1,871)	(41)	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders						(38)
Contributions	82	0	82	0	0	0
Other	13	4	0	0	9	0
Ending Balance at Dec. 31, 2022	12,546	8,413	3,293	611	(8)	237
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,872	1,336	2,493	5	0	38
Conversion of Series A preferred units	(73)	(73)	0	0	0	0
Partners' Capital Account, Redemptions	600	2	3	595	0	0
Distributions	(3,243)	(1,125)	(2,056)	(21)	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders						(41)
Contributions	31	0	31	0	0	0
Other	10	5	0	0	4	1
Ending Balance at Dec. 31, 2023	12,689	8,700	3,758	0	(4)	235
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,330	1,555	2,735	0	0	40
Unit repurchases	(326)	(326)	0	0	0	0
Conversion of Series A preferred units	675	675	0	0	0	0
Distributions	(3,603)	(1,289)	(2,270)	0	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders						(44)
Contributions	34	0	34	0	0	0
Other	8	7	0	0	1	0
Ending Balance at Dec. 31, 2024	$ 13,807	$ 9,322	$ 4,257	$ 0	$ (3)	$ 231

Consolidated Statements of Eq_2

Consolidated Statements of Equity and Series A Preferred Units (Temporary Equity) - USD ($) $ in Millions	Total	Series A Preferred Unit-holders
Beginning Balance at Dec. 31, 2021		$ 965
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income		88
Distributions		85
Ending Balance at Dec. 31, 2022		968
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income		94
Conversion of Series A preferred units		73
Distributions		94
Ending Balance at Dec. 31, 2023	$ 895	895
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income		27
Conversion of Series A preferred units		675
Distributions		44
Ending Balance at Dec. 31, 2024	$ 203	$ 203

Description of Business and Bas

Description of Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2024
Limited Liability Company or Limited Partnership, Business Organization and Operations [Abstract]
Business Description and Basis of Presentation [Text Block]	Description of the Business and Basis of Presentation Description of the Business MPLX LP is a diversified, large-cap master limited partnership formed by Marathon Petroleum Corporation that owns and operates midstream energy infrastructure and logistics assets, and provides fuels distribution services. References in this report to “MPLX LP,” “MPLX,” “the Partnership,” “we,” “ours,” “us,” or like terms refer to MPLX LP and its subsidiaries. References to our sponsor and customer, “MPC,” refer collectively to Marathon Petroleum Corporation and its subsidiaries, other than the Partnership. We are engaged in the gathering, transportation, storage and distribution of crude oil, refined products, other hydrocarbon-based products and renewables; the gathering, processing and transportation of natural gas; and the transportation, fractionation, storage and marketing of NGLs. MPLX’s principal executive office is located in Findlay, Ohio. MPLX was formed on March 27, 2012 as a Delaware limited partnership and completed its initial public offering on October 31, 2012. MPLX’s business consists of two segments. In the fourth quarter of 2024, we renamed and modified the composition of our segments to better reflect the product-based value chains and growth strategy of MPLX’s operations. The primary changes were to rename the Logistics and Storage segment to the Crude Oil and Products Logistics segment and to rename the Gathering and Processing segment to the Natural Gas and NGL Services segment. In addition, we reclassified certain equity method investments serving natural gas and NGL customers from Crude Oil and Products Logistics to Natural Gas and NGL Services. The segment realignment is presented for the year ended December 31, 2024, with prior periods recast for comparability. The Crude Oil and Products Logistics segment includes the gathering, transportation, storage and distribution of crude oil, refined products, other hydrocarbon-based products and renewables. The Natural Gas and NGL Services segment gathers, processes and transports natural gas; and transports, fractionates, stores and markets NGLs. See Note 10 for additional information regarding the operations and results of these segments. Basis of Presentation The accompanying consolidated financial statements of MPLX have been prepared in accordance with GAAP. The consolidated financial statements include all majority-owned and controlled subsidiaries. For non-wholly-owned consolidated subsidiaries, the interests owned by third parties have been recorded as Noncontrolling interests on the accompanying Consolidated Balance Sheets. Intercompany accounts and transactions have been eliminated. MPLX’s investments in which MPLX exercises significant influence but does not control and does not have a controlling financial interest are accounted for using the equity method. MPLX’s investments in VIEs, in which MPLX exercises significant influence but does not control and is not the primary beneficiary, are also accounted for using the equity method. Certain prior period financial statement amounts have been reclassified to conform to current period presentation.

Summary of Principal Accounting

Summary of Principal Accounting Policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Summary of Principal Accounting Policies Use of Estimates The preparation of financial statements in accordance with GAAP 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. Actual results could differ materially from those estimates. Estimates are subject to uncertainties due to the levels of subjectivity and judgment necessary to account for highly uncertain matters or the susceptibility of such matters to change and affect items such as valuing identified intangible assets; determining the fair value of derivative instruments; evaluating impairments of long-lived assets, goodwill and equity investments; establishing estimated useful lives for long-lived assets; acquisition accounting; estimating revenues, expense accruals and capital expenditures; valuing AROs; recognizing share-based compensation expense; and determining liabilities, if any, for environmental and legal contingencies. Revenue Recognition Revenue is measured based on consideration specified in a contract with a customer. MPLX recognizes revenue when it satisfies a performance obligation by transferring control over a product or providing services to a customer. MPLX enters into a variety of contract types in order to generate Product sales and Service revenue. MPLX provides services under the following types of arrangements: • Fee-based arrangements – Under fee-based arrangements, MPLX receives fees for the following services: gathering, processing and transportation of natural gas; transportation, fractionation, exchange and storage of NGLs; and transportation, terminalling, storage and distribution of crude oil, refined products, other hydrocarbon-based products, and renewables. The revenue MPLX earns from these arrangements is generally directly related to the volume of natural gas, NGLs, refined products or crude oil that is handled by or flows through MPLX’s systems and facilities and is not normally directly dependent on commodity prices. In certain cases, MPLX’s arrangements provide for minimum volume commitments. Fee-based arrangements are reported as Service revenue on the Consolidated Statements of Income. Revenue is recognized over time as services are performed. In certain instances when specifically stated in the contract terms, MPLX purchases product after fee-based services have been provided. Revenue from the sale of products purchased after services are provided is reported as Product sales on the Consolidated Statements of Income and recognized on a gross basis, as MPLX takes control of the product and is the principal in the transaction. • Percent-of-proceeds arrangements – Under percent-of-proceeds arrangements, MPLX gathers and processes natural gas on behalf of producers; sells the resulting residue gas, condensate and NGLs at market prices; and remits to producers an agreed-upon percentage of the proceeds. In other cases, instead of remitting cash payments to the producer, MPLX delivers an agreed-upon percentage of the residue gas and NGLs to the producer (take-in-kind arrangements) and sells the volumes MPLX retains to third parties or related parties. Revenue is recognized on a net basis when MPLX acts as an agent and does not have control of the gross amount of gas and/or NGLs prior to it being sold. Percent-of-proceeds revenue is reported as Service revenue - product related on the Consolidated Statements of Income. • Keep-whole arrangements – Under keep-whole arrangements, MPLX gathers natural gas from the producer, processes the natural gas and sells the resulting condensate and NGLs to third parties at market prices. Because the extraction of the condensate and NGLs from the natural gas during processing reduces the Btu content of the natural gas, MPLX must either purchase natural gas at market prices for return to producers or make cash payment to the producers equal to the value of the energy content of this natural gas. Certain keep-whole arrangements also have provisions that require MPLX to share a percentage of the keep-whole profits with the producers based on the oil to gas ratio or the NGL to gas ratio. Service revenue - product related is recorded based on the value of the NGLs received on the date the services are performed. Natural gas purchased to return to the producer and shared NGL profits are recorded as a reduction of Service revenue - product related on the Consolidated Statements of Income on the date the services are performed. Sales of NGLs under these arrangements are reported as Product sales on the Consolidated Statements of Income and are reported on a gross basis as MPLX is the principal in the arrangement and controls the product prior to sale. The sale of the NGLs may occur shortly after services are performed at the tailgate of the plant, or after a period of time as determined by MPLX. • Purchase arrangements – Under purchase arrangements, MPLX purchases natural gas at either the wellhead or the tailgate of a plant. MPLX then gathers and delivers the natural gas to pipelines where MPLX may resell the natural gas. Wellhead purchase arrangements represent an arrangement with a supplier and are recorded in Purchased product costs. Often, MPLX earns fees for services performed prior to taking control of the product in these arrangements and Service revenue is recorded for these fees. Revenue generated from the sale of product obtained in tailgate purchase arrangements is reported as Product sales on the Consolidated Statements of Income and is recognized on a gross basis as MPLX purchases and takes control of the product prior to sale and is the principal in the transaction. In many cases, MPLX provides services under contracts that contain a combination of more than one of the arrangements described above. When fees are charged (in addition to product received) under percent-of-proceeds arrangements, keep-whole arrangements or purchase arrangements, MPLX records such fees as Service revenue on the Consolidated Statements of Income. The terms of MPLX’s contracts vary based on gas quality conditions, the competitive environment when the contracts are signed, and customer requirements. Performance obligations are determined based on the specific terms of the arrangements, economics of the geographical regions, and the services offered and whether they are deemed distinct. MPLX allocates the consideration earned between the performance obligations based on the stand-alone selling price when multiple performance obligations are identified. Revenue from MPLX’s service arrangements will generally be recognized over time as the performance obligation is satisfied as services are provided. MPLX has elected to use the output measure of progress to recognize revenue based on the units delivered, processed or transported. The transaction price may have fixed components related to minimum volume commitments and variable components, which are primarily dependent on volumes. Variable consideration will generally not be estimated at contract inception as the transaction price is specifically allocable to the services provided each period. In instances in which tiered pricing structures do not reflect our efforts to perform, MPLX will estimate variable consideration at contract inception. Product sales will be recognized at a point in time when control of the product transfers to the customer. Minimum volume commitments may create contract liabilities if current period payments can be used for future services. If a customer fails to meet its minimum committed volumes, it owes MPLX a deficiency payment based on the terms of the applicable agreement. The deficiency amounts received under these agreements (excluding payments received under agreements classified as sales-type leases) are recorded as Current liabilities or Current liabilities - related parties. In many cases, the customer may then apply the amount of any such deficiency payments as a credit for volumes in excess of its minimum volume commitment in future periods under the terms of the applicable agreements. MPLX recognizes revenue for the deficiency payments when credits are used for volumes in excess of minimum quarterly volume commitments, where it is probable the customer will not use the credit in future periods or upon the expiration of the credits. The use or expiration of the credits is a decrease in Current liabilities or Current liabilities - related parties. Deficiency payments under agreements that have been classified as sales-type leases are recorded as a reduction against the corresponding lease receivable. Amounts billed to customers for shipping and handling, electricity, and other costs to perform services are included in the transaction price as a component of Revenues and other income on the Consolidated Statements of Income. Shipping and handling costs associated with product sales are included in Purchased product costs on the Consolidated Statements of Income. Customers usually pay monthly based on the products purchased or services performed that month. Taxes collected from customers and remitted to the appropriate taxing authority are excluded from revenue. Based on the terms of certain contracts, MPLX is considered to be the lessor under several implicit operating and sales-type lease arrangements in accordance with GAAP. Revenue and costs related to the portion of the revenue earned under these contracts considered to be implicit operating leases are recorded as Rental income and Rental cost of sales, respectively, on the Consolidated Statements of Income. Revenue related to the portion of the revenue earned under these contracts considered to be implicit sales-type lease arrangements is recorded as Sales-type lease revenue on the Consolidated Statements of Income, while related costs are recorded to Cost of revenues or Purchases - related parties. Revenue and Expense Accruals MPLX routinely makes accruals based on estimates for both revenues and expenses due to the timing of compiling billing information, receiving certain third-party information and reconciling MPLX’s records with those of third parties. The delayed information from third parties includes, among other things, actual volumes purchased, transported or sold, adjustments to inventory and invoices for purchases, actual natural gas and NGL deliveries, and other operating expenses. MPLX makes accruals to reflect estimates for these items based on its internal records and information from third parties. Estimated accruals are adjusted when actual information is received from third parties and MPLX’s internal records have been reconciled. Other Taxes Other taxes primarily include real estate taxes. Cash and Cash Equivalents Cash and cash equivalents include cash on hand and on deposit and investments in highly liquid debt instruments with original maturities of three months or less. Receivables Receivables primarily consist of customer accounts receivable, which are recorded at the invoiced amount and generally do not bear interest. Allowances for doubtful accounts are generally recorded when it becomes probable that the receivable will not be collected and are recorded to bad debt expense. We review the allowance quarterly and past-due balances over 150 days are reviewed individually for collectability. Balances that remain outstanding after reasonable collection efforts have been unsuccessful are written off through a charge to the valuation allowance and a credit to accounts receivable. Leases Contracts with a term greater than one year that convey the right to direct the use of and obtain substantially all of the economic benefit of an asset are accounted for as right of use (“ROU”) assets and lease liabilities. ROU asset and lease liability balances are recorded at the commencement date at present value of the fixed lease payments using a secured incremental borrowing rate with a maturity similar to the lease term because our leases do not provide implicit rates. We have elected to include both lease and non-lease components in the present value of the lease payments for all lessee asset classes with the exception of our marine and third-party contractor service and equipment leases. The lease component of the payment for the marine and equipment asset classes is determined using a relative standalone selling price. Operating lease expense is recognized on a straight-line basis over the lease term. See Note 21 for additional disclosures about our lease contracts. As a lessor under ASC 842, MPLX may be required to re-classify existing operating leases to sales-type leases upon modification and related reassessment of the leases. See Note 21 for further information regarding our ongoing evaluation of the impacts of lease reassessments as modifications occur. The net investment in sales-type leases with third parties is recorded within Receivables, net and Other noncurrent assets on the Consolidated Balance Sheets. The net investment in sales-type leases with related parties is recorded within Current assets - related parties and Noncurrent assets - related parties on the Consolidated Balance Sheets. These amounts are comprised of the present value of the sum of the future minimum lease payments representing the value of the lease receivable and the unguaranteed residual value of the leased assets. Management assesses the net investment in sales-type leases for recoverability quarterly. Inventories Inventories consist of materials and supplies to be used in operations, line fill and other NGLs. Cost for materials and supplies are determined primarily using the weighted-average cost method. Inventories are valued at the lower of cost or net realizable value. Imbalances Within our pipelines and storage assets, we experience volume gains and losses due to pressure and temperature changes, evaporation and variances in meter readings and other measurement methods. Until settled, positive imbalances are recorded as other current assets and negative imbalances are recorded as accounts payable. Positive and negative imbalances are settled in cash, settled by physical delivery of volumes from a different source, or tracked and settled in the future. Investment in Unconsolidated Affiliates Equity investments in which MPLX exercises significant influence but does not control and is not the primary beneficiary, are accounted for using the equity method and are reported in Equity method investments on the accompanying Consolidated Balance Sheets. This includes entities in which we hold majority ownership, but the minority shareholders have substantive participating rights. 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. Regular evaluation of these investments is appropriate to evaluate any potential need for impairment. MPLX uses evidence of a loss in value to identify if an investment has an other than a temporary decline. Impairments are recorded through Income from equity method investments. 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. Expenditures that extend the useful lives of assets are capitalized. Long-lived assets used in operations are assessed for impairment whenever changes in facts and circumstances indicate that the carrying value of the assets may not be recoverable based on the expected undiscounted future cash flows of an asset group. For purposes of impairment evaluation, long-lived assets must be grouped at the lowest level for which independent cash flows can be identified, which is at least at the segment level and in some cases for similar assets in the same geographic region where cash flows can be separately identified. If the sum of the undiscounted future cash flows from the use of the asset group and its eventual disposition is less than the carrying value of an asset group, an impairment assessment is performed and the excess of the book value over the fair value is recorded as an impairment loss. When items of property, plant and equipment are sold or otherwise disposed of, any gains or losses are reported on the Consolidated Statements of 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 costs for the construction or development of long-lived assets are capitalized and amortized over the related asset’s estimated useful life. Goodwill and Intangibles 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 at the reporting unit level 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. If we determine, based on a qualitative assessment, that it is not more likely than not that a reporting unit’s fair value is less than its carrying amount, no further impairment testing is required. If we do not perform a qualitative assessment or if that assessment indicates that further impairment testing is required, the fair value of each reporting unit is determined using an income and market approach which is compared to the carrying value of the reporting unit. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss would be recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit. The fair value under the income approach is calculated using the expected present value of future cash flows method. Significant assumptions used in the cash flow forecasts include future volumes, discount rates, and future capital requirements. See Note 14 for further details. 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. Environmental Costs Environmental expenditures for additional equipment that mitigates or prevents future contamination or improves environmental safety or efficiency of the existing assets are capitalized. 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 the 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 An ARO is a legal obligation associated with the retirement of tangible long-lived assets that generally result from the acquisition, construction, development or normal operation of the asset. The fair value of AROs is recognized in the period in which the obligations are incurred, if a reasonable estimate of fair value can be made, and added to the carrying amount of the associated asset. This additional carrying amount is then depreciated over the life of the asset. The liability is determined using a credit adjusted risk free interest rate and increases due to the passage of time based on the time value of money until the obligation is settled. AROs have not been recognized for certain 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. As of December 31, 2024 and 2023, MPLX’s asset retirement obligation was $41 million and $39 million, respectively, and is included on the balance sheet within Other long-term liabilities. Derivative Instruments MPLX may use commodity derivatives to economically hedge a portion of its exposure to commodity price risk. All derivative instruments (including derivatives embedded in other contracts) are recorded at fair value. MPLX discloses the fair value of all derivative instruments under the captions Other current assets, Other noncurrent assets, Other current liabilities and Other long-term liabilities on the Consolidated Balance Sheets. Certain commodity derivative positions are governed by master netting arrangements and are reflected on the consolidated balance sheets on a net basis by counterparty. We make a distinction between realized or unrealized gains and losses on derivatives. During the period when a derivative contract is outstanding, changes in the fair value of the derivative are recorded as an unrealized gain or loss. When a derivative contract matures or is settled, the previously recorded unrealized gain or loss is reversed, and the realized gain or loss of the contract is recorded. Changes in the fair value of derivative instruments are reported on the Consolidated Statements of Income in accounts related to the item whose value or cash flows are being managed. Derivative instruments are marked to market through Product sales and Purchased product costs on the Consolidated Statements of Income. During the years ended December 31, 2024, 2023 and 2022, MPLX did not elect hedge accounting for any derivatives. MPLX has historically elected the normal purchases and normal sales designation for certain contracts related to the physical purchase of electric power and the sale of most commodities. Fair Value Measurement Financial assets and liabilities recorded at fair value in the Consolidated Balance Sheets are categorized based upon the fair value hierarchy established by GAAP, which classifies the inputs used to measure fair value into Level 1, Level 2 or Level 3. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The methods and assumptions utilized may produce a fair value that may not be realized in future periods upon settlement. Furthermore, while MPLX believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. For further discussion, see Note 15. Equity-Based Compensation Arrangements MPLX issues phantom units under the MPLX LP 2018 Incentive Compensation Plan. A phantom unit entitles the grantee a right to receive a common unit upon the issuance of the phantom unit. The fair value of phantom unit awards granted to employees and non-management directors is based on the fair market value of MPLX LP common units on the date of grant. The fair value of the units awarded is amortized into earnings using a straight-line amortization schedule over the period of service corresponding with the vesting period. For phantom units that vest immediately and are not forfeitable, equity-based compensation expense is recognized at the time of grant. To satisfy common unit awards, MPLX may issue new common units, acquire common units in the open market or use common units already owned by the general partner. Income Taxes MPLX is not a taxable entity for United States federal income tax purposes or for the majority of the states that impose an income tax. Taxes on MPLX’s net income generally are borne by its partners through the allocation of taxable income. MPLX’s taxable income or loss, which may vary substantially from the net income or loss reported on the Consolidated Statements of Income, is includable in the federal income tax returns of each partner. MPLX and certain legal entities are, however, taxable entities under certain state jurisdictions. MPLX accounts for income taxes under the asset and liability method. Deferred income taxes are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis, capital loss carryforwards and net operating loss and credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of any tax rate change on deferred taxes is recognized as tax expense/(benefit) from continuing operations in the period that includes the enactment date of the tax rate change. Realizability of deferred tax assets is assessed and, if not more likely than not, a valuation allowance is recorded to reflect the deferred tax assets at net realizable value as determined by management. All deferred tax balances are classified as long-term in the accompanying Consolidated Balance Sheets. All changes in the tax bases of assets and liabilities are allocated among operations and items charged or credited directly to equity. Distributions In preparing the Consolidated Statements of Equity, net income attributable to MPLX LP is allocated to preferred unitholders based on a fixed distribution schedule, as discussed in Notes 7 and 9, and subsequently allocated to the limited partner unitholders. Distributions, although earned, are not accrued as a liability until declared. The allocation of net income attributable to MPLX LP for purposes of calculating net income per limited partner unit is described below. Net Income Per Limited Partner Unit MPLX uses the two-class method when calculating the net income per unit applicable to limited partners, because there is more than one class of participating security. The classes of participating securities include common units, preferred units and certain equity-based compensation awards. Net income attributable to MPLX LP is allocated to the unitholders differently for preparation of the Consolidated Statements of Equity and the calculation of net income per limited partner unit. In preparing the Consolidated Statements of Equity, net income attributable to MPLX LP is allocated to preferred unitholders based on a fixed distribution schedule and subsequently allocated to remaining unitholders in accordance with their respective ownership percentages. The allocation of net income attributable to MPLX LP for purposes of calculating net income per limited partner unit is described in Note 8. In preparing net income per limited partner units, during periods in which a net loss attributable to MPLX is reported or periods in which the total distributions exceed the reported net income attributable to MPLX’s unitholders, the amount allocable to certain equity-based compensation awards is based on actual distributions to the equity-based compensation awards. Diluted earnings per unit is calculated by dividing net income attributable to MPLX’s common unitholders, after deducting amounts allocable to other participating securities, by the weighted average number of common units and potential common units outstanding during the period. Potential common units are excluded from the calculation of diluted earnings per unit during periods in which net income attributable to MPLX’s unitholders, after deducting amounts that are allocable to the outstanding equity-based compensation awards and preferred units, is a loss, as the impact would be anti-dilutive. 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. Any excess or deficit of the purchase consideration when compared to the fair value of the net tangible assets acquired, if any, is recorded as goodwill or gain from a bargain purchase. Depending on the nature of the transaction, management may engage an independent valuation specialist to assist with the determination of fair value of the assets acquired, liabilities assumed, noncontrolling interests, if any, and goodwill, based on recognized business valuation methodologies. An income, market or cost valuation method may be utilized to estimate the fair value of the assets acquired, liabilities assumed, and noncontrolling interests, 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 volumes, certain commodity prices, 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. 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, MPLX will record any material adjustments to the initial estimate based on new information obtained that would have existed as of the acquisition date. Any adjustment that arises from information obtained that did not exist as of the date of the acquisition will be recorded in the period of the adjustment. Acquisition-related costs are expensed as incurred in connection with each business combination. Acquisitions in which the company or business being acquired by MPLX had an existing relationship with MPC may result in the transaction being considered a transfer between entities under common control. In these situations, MPLX records the assets acquired and liabilities assumed on its consolidated balance sheets at MPC’s historical carrying value. For the acquiring entity, transfers of businesses between entities under common control require prior periods to be retrospectively adjusted for those dates that the entity was under common control.

Accounting Standards

Accounting Standards	12 Months Ended
	Dec. 31, 2024
Accounting Standards Update and Change in Accounting Principle [Abstract]
Accounting Standards	Accounting Standards and Disclosure Rules Recently Adopted ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures The FASB issued this ASU to update reportable segment disclosure requirements primarily by requiring enhanced disclosures about significant segment expenses. During the fourth quarter of 2024, we applied the amendments in this ASU retrospectively to all periods presented in the financial statements. The enhanced disclosures for significant segment expenses are presented in Note 10 - Segment Information. ASU 2023-01, Leases (Topic 842): Common Control Arrangements The FASB issued this ASU to amend certain provisions of ASC 842 that apply to arrangements between related parties under common control. The ASU amends the accounting for the amortization period of leasehold improvements in common-control leases for all entities and requires certain disclosures when the lease term is shorter than the useful life of the asset. During the first quarter of 2024, we adopted this ASU and it did not have a material impact on our financial statements or disclosures. Not Yet Adopted ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses In November 2024, the FASB issued an ASU to require more detailed information about specified categories of expenses (purchases of inventory, employee compensation, depreciation, amortization, and depletion) included in certain expense captions presented on the income statement. This ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The amendments may be applied either (1) prospectively to financial statements issued for reporting periods after the effective date of this ASU or (2) retrospectively to all prior periods presented in the financial statements. We are currently evaluating the impact this ASU will have on our disclosures. SEC Release No. 33-11275, The Enhancement and Standardization of Climate-Related Disclosures for Investors In March 2024, the SEC adopted rules under SEC Release No. 33-11275, The Enhancement and Standardization of Climate-Related Disclosures for Investors, which requires registrants to provide certain climate-related information in their annual reports. As part of the disclosures, material impacts from severe weather events and other natural conditions will be required in the audited financial statements. In April 2024, the SEC voluntarily stayed the rules pending judicial review. Pending the results of the judicial review, the disclosure requirements are effective for the Partnership’s Annual Report on Form 10-K for the fiscal year ending December 31, 2025. We are evaluating the impact these rules, if effective, will have on our disclosures and monitoring the status of the judicial review.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2024
Business Combinations [Abstract]
Mergers, Acquisitions and Dispositions Disclosures	Acquisitions and Other Transactions BANGL, LLC Acquisition On July 31, 2024, MPLX exercised its right of first offer under the BANGL, LLC joint venture agreement to purchase an additional 20 percent ownership interest in BANGL, LLC, for $210 million cash, increasing total ownership interest to 45 percent (the “BANGL Transaction”). BANGL, LLC owns a natural gas liquids pipeline system connecting the Delaware and Midland basins to the fractionation market in the Gulf Coast and export markets. The purchase price of the additional 20 percent ownership interest in BANGL, LLC exceeded our portion of the underlying net assets of the joint venture by approximately $156 million. This basis difference is being amortized into net income over the remaining estimated useful lives of the underlying net assets. Following the BANGL Transaction, our investment in BANGL, LLC continues to be accounted for as an equity method investment. Whistler Joint Venture Transaction On May 29, 2024, MPLX and its joint venture partner contributed their respective membership interest in Whistler Pipeline, LLC to a newly formed joint venture, WPC Parent, LLC, and issued a 19 percent voting interest in WPC Parent, LLC to an affiliate of Enbridge Inc. in exchange for the contribution of cash and the Rio Bravo Pipeline project (the “Whistler Joint Venture Transaction”). As a result of the transaction, MPLX’s voting interest in the joint venture was reduced from 37.5 percent to 30.4 percent. MPLX recognized a gain of $151 million at closing and received a cash distribution of $134 million, recorded as a return of capital, related to the dilution of the ownership interest. The gain is included in Income from equity method investments on the accompanying consolidated statements of income and the return of capital is included in Investments - redemptions, repayments, return of capital and sales proceeds within the investing section of the accompanying consolidated statements of cash flows. Utica Midstream Acquisition On March 22, 2024, MPLX used $625 million of cash on hand to purchase additional ownership interest in existing joint ventures and gathering assets (the “Utica Midstream Acquisition”), which will enhance our position in the Utica basin. Prior to the acquisition, we owned an indirect interest in Ohio Gathering Company L.L.C. (“OGC”) and a direct interest in Ohio Condensate Company L.L.C. (“OCC”) and now own a combined 73 percent interest in OGC, a 100 percent interest in OCC, and a 100 percent interest in a dry gas gathering system in the Utica basin, including 53 miles of gathering pipeline and three dehydration units with a combined capacity of approximately 620 MMcf/d. OGC continues to be accounted for as an equity method investment, as MPLX did not obtain control of OGC as a result of the transaction. The acquisition date fair value of our investment in OGC exceeded our portion of the underlying net assets of the joint venture by approximately $75 million. This basis difference is being amortized into net income over the remaining estimated useful lives of the underlying net assets. OCC was previously accounted for as an equity method investment, and it is now reflected as a consolidated subsidiary within our consolidated financial results. The results for the acquired business are reported within our Natural Gas and NGL Services segment. The Utica Midstream Acquisition was accounted for as a business combination requiring all the acquired assets and liabilities to be remeasured to fair value resulting in a consolidated fair value of net assets and liabilities of $625 million. The fair value includes $507 million related to acquired interests in the joint ventures and the remaining balance related to other acquired assets and liabilities. The revaluation of MPLX’s existing 62 percent equity method investment in OCC resulted in a $20 million gain, which is included in Other income within the accompanying consolidated statements of income. The fair value of equity method investments was based on a discounted cash flow model. Acquisition of 40 Percent Interest in MarkWest Torñado GP, L.L.C. On December 15, 2023, MPLX used $303 million of cash on hand to purchase the remaining 40 percent interest in MarkWest Torñado GP, L.L.C. (“Torñado”) for approximately $270 million, including cash paid for working capital, and to extend the term of a gathering and processing agreement for approximately $33 million. As a result of this transaction, we now own 100 percent of Torñado and reflect it as a consolidated subsidiary within our consolidated financial results. It was previously accounted for as an equity method investment. Torñado provides natural gas gathering and processing related services in the Permian basin. Its assets include two gas processing plants, each with a capacity of 200 MMcf/d and approximately 142 miles of gathering pipeline. The results for this business are reported under our Natural Gas and NGL Services segment. At December 15, 2023, the carrying value of our 60 percent equity investment in Torñado was $311 million. Upon acquisition of the remaining 40 percent member interest, our existing equity investment was remeasured to fair value resulting in the recognition of a $92 million gain, which is presented in Other income on the Consolidated Statements of Income. The fair value of the previously-held equity method investment was primarily based on the price negotiated for the 40 percent interest in Torñado. The acquisition was accounted for as a business combination requiring all of the Torñado assets and liabilities to be remeasured to fair value resulting in a consolidated fair value of net assets and liabilities of $673 million. The fair value of property, plant and equipment was based primarily on the cost approach. The fair value of the identifiable intangible assets, consisting of various customer contracts, was primarily based on the multi-period excess earnings method, which is an income approach. The following table reflects our determination of the fair value of the Torñado assets and liabilities (in millions): (In millions) Property, Plant and Equipment $ 585 Intangibles 75 Working capital, net 30 Other Long-term assets and liabilities, net (17) Total net assets and liabilities $ 673 Pro forma financial information assuming the acquisition had occurred as of the beginning of the calendar year prior to the year of the acquisition, as well as the revenues and earnings generated during the period since the acquisition date, were not material for disclosure purposes.

Investments and Noncontrolling

Investments and Noncontrolling Interests	12 Months Ended
	Dec. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Investments and Noncontrolling Interests	Investments and Noncontrolling Interests The following table presents MPLX’s equity method investments at the dates indicated: Ownership as of Carrying value at December 31, December 31, (In millions, except ownership percentages) VIE 2024 2024 2023 Crude Oil and Products Logistics Illinois Extension Pipeline Company, L.L.C. 35% $ 218 $ 228 LOOP LLC 41% 310 314 MarEn Bakken Company LLC (1) 25% 526 449 Other (2) X 541 526 Total Crude Oil and Products Logistics 1,595 1,517 Natural Gas and NGL Services BANGL, LLC (3) 45% 281 63 MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C. X 67% 329 336 MarkWest Utica EMG, L.L.C. X 59% 742 676 Ohio Gathering Company L.L.C. (4) X 35% 470 — Sherwood Midstream LLC X 50% 488 500 WPC Parent, LLC (5) 30% 208 214 Other (2) X 418 437 Total Natural Gas and NGL Services 2,936 2,226 Total $ 4,531 $ 3,743 (1) The investment in MarEn Bakken Company LLC includes our 9.19 percent indirect interest in a joint venture (“Dakota Access”) that owns and operates the Dakota Access Pipeline and Energy Transfer Crude Oil Pipeline projects (collectively referred to as the “Bakken Pipeline system”). (2) Some investments included within Other have also been deemed to be VIEs. (3) In July 2024, we purchased an additional 20 percent ownership interest in BANGL, LLC, increasing our ownership interest to 45 percent, as discussed in Note 4. (4) We acquired a 36 percent direct interest in OGC in the Utica Midstream Acquisition discussed in Note 4. We also hold a 38 percent indirect interest in OGC through our ownership interest in MarkWest Utica EMG, L.L.C. (5) Reflects the dilution of MPLX’s ownership interest in Whistler Pipeline, LLC and the formation of a new entity, WPC Parent, LLC, as discussed in Note 4. The carrying value at December 31, 2024 represents our ownership in WPC Parent, LLC, and the carrying value at December 31, 2023 represents our ownership interest in Whistler Pipeline, LLC. For those entities that have been deemed to be VIEs, neither MPLX nor any of its subsidiaries have been deemed to be the primary beneficiary due to voting rights on significant matters. While we have the ability to exercise influence through participation in the management committees which make all significant decisions, we have equal influence over each committee as a joint interest partner and all significant decisions require the consent of the other investors without regard to economic interest. As such, we have determined that these entities should not be consolidated and applied the equity method of accounting with respect to our investments in each entity. MPLX’s maximum exposure to loss as a result of its involvement with equity method investments generally includes its equity investment, any additional capital contribution commitments and any operating expenses incurred by the subsidiary operator in excess of its compensation received for the performance of the operating services. MPLX did not provide any financial support to equity method investments that it was not contractually obligated to provide during the years ended December 31, 2024, 2023 and 2022. See Note 22 for information on our guarantees related to equity method investees. From time to time, changes in the design or nature of the activities of our equity method investments may require us to reconsider our conclusions on the entity’s status as a VIE and/or our status as the primary beneficiary. Such reconsideration could result in a change in the classification of the equity method investment. Summarized financial information for MPLX’s equity method investments is as follows: (In millions) 2024 2023 2022 Income statement data: Revenues and other income $ 3,594 $ 3,262 $ 2,653 Costs and expenses 1,535 1,331 1,251 Income from operations 2,059 1,930 1,402 Net income 1,631 1,634 1,246 Balance sheet data: Current assets 1,570 1,531 Noncurrent assets 17,927 13,860 Current liabilities 746 979 Noncurrent liabilities 6,711 4,856 As of December 31, 2024 and 2023, the carrying value of MPLX’s equity method investments in the Crude Oil and Products Logistics segment exceeded the underlying net assets of its investees by $291 million and $299 million, respectively. As of December 31, 2024, the carrying value of its equity method investments in the Natural Gas and NGL Services segment exceeded the underlying net assets of its equity method investments by approximately $198 million. As of December 31, 2023, the underlying net assets of MPLX’s investees in the Natural Gas and NGL Services segment exceeded the carrying value of its equity method investments by approximately $30 million.

Related Party Agreements and Tr

Related Party Agreements and Transactions	12 Months Ended
	Dec. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	Related Party Agreements and Transactions MPLX engages in transactions with both MPC and certain of its equity method investments as part of its normal business; however, transactions with MPC make up the majority of MPLX’s related party transactions. Transactions with related parties are further described below. Commercial Agreements MPLX has various long-term, fee-based commercial agreements with MPC. Under these agreements, MPLX provides transportation, gathering, terminal, fuels distribution, marketing, storage, management, operational and other services to MPC. MPC has committed to provide MPLX with minimum quarterly throughput volumes on crude oil and refined products and other fees for storage capacity; operating and management fees; and reimbursements for certain direct and indirect costs. MPC has also committed to provide a fixed fee for 100 percent of available capacity for boats, barges and third-party chartered equipment under the marine transportation service agreements. The commercial agreements with MPC include: • MPLX has a fuels distribution agreement with MPC under which MPC pays MPLX a tiered monthly volume-based fee for marketing and selling MPC’s products. This agreement is subject to a minimum quarterly volume and has an initial term of 10 years, subject to a five • MPLX has various pipeline transportation agreements under which MPC pays MPLX fees for transporting crude and refined products on MPLX’s pipeline systems. These agreements are subject to minimum throughput volumes under which MPC will pay MPLX deficiency payments for any period in which they do not ship the minimum committed volume. Under certain agreements, deficiency payments can be applied as credits to future periods in which MPC ships volumes in excess of the minimum volume, subject to a limited period of time. These agreements are subject to various terms and renewal periods. • MPLX has marine transportation agreements with initial terms of five • MPLX has numerous storage services agreements governing storage services at various types of facilities including terminals, pipeline tank farms, caverns and refineries, under which MPC pays MPLX per-barrel fees for providing storage services. Some of these agreements provide MPC with exclusive access to storage at certain locations, such as storage located at MPC’s refineries or storage in certain caverns. Under these agreements, MPC pays MPLX a per-barrel fee for such storage capacity, regardless of whether MPC fully utilizes the available capacity. These agreements are subject to various terms and renewal periods. • MPLX has multiple terminal services agreements governing certain terminals under which MPC pays MPLX fees for terminal services. Under these agreements MPC pays MPLX agreed upon fees relating to MPC product receipts, deliveries and storage as well as any blending, additization, handling, transfers or other related charges. Many of these agreements are subject to minimum volume throughput commitments, or to various minimum commitments related to some or all terminal activities, under which MPC pays a deficiency payment for any period in which they do not meet the minimum commitment. Some of these agreements allow for deficiency payments to be applied as credits to a limited number of future periods with excess throughput volumes. These agreements are subject to various terms and renewal periods. • MPLX has a keep-whole commodity agreement with MPC under which MPC pays us a processing fee for NGLs related to keep-whole agreements and we pay MPC a marketing fee in exchange for assuming the commodity risk. The pricing structure under this agreement provides for a base volume subject to a base rate and incremental volumes subject to variable rates, which are calculated with reference to certain of our costs incurred as processor of the volumes. The pricing for both the base and incremental volumes are subject to revision each year. This agreement is subject to automatic three-month renewal periods. This agreement is scheduled to expire in 2025. • MPLX has an agreement with MPC under which it provides management services to assist MPC in the oversight and management of the marine business. MPLX receives fixed annual fees for providing the required services, which are subject to predetermined annual escalation rates. This agreement is subject to an initial term of five years and automatically renews for one additional five In many cases, agreements are location-based hybrid agreements, containing provisions relating to multiple of the types of agreements and services described above. Operating Agreements MPLX operates various pipelines owned by MPC under operating services agreements. Under these operating services agreements, MPLX receives a fee for operating the assets and is reimbursed for all associated direct and indirect costs. Most of these agreements are indexed for inflation. These agreements range from one MPLX also receives management fee revenue for engineering, construction and administrative services for operating certain of its equity method investments. Amounts earned under these management agreements are classified as Other income-related parties in the Consolidated Statements of Income. Co-location Services Agreements MPLX is party to co-location services agreements with MPC’s refineries under which MPC provides management, operational and other services to MPLX. MPLX pays MPC monthly fixed fees and direct reimbursements for such services calculated as set forth in the agreements. These agreements have initial terms of 50 years. Ground Lease Agreements MPLX is party to ground lease agreements with certain of MPC’s refineries under which MPLX is the lessee of certain sections of property which contain facilities owned by MPLX and are within the premises of MPC’s refineries. MPLX pays MPC monthly fixed fees under these ground leases. These agreements are subject to various terms. Omnibus Agreements MPLX has omnibus agreements with MPC that address MPLX’s payment of fixed annual fees to MPC for the provision of executive management services by certain executive officers of the general partner and MPLX’s reimbursement of MPC for the provision of certain general and administrative services to it (“Omnibus Charges”). They also provide for MPC’s indemnification to MPLX for certain matters, including environmental, title and tax matters, as well as our indemnification of MPC for certain matters under these agreements. The omnibus agreements also provide for other reimbursements, including certain capital and expense projects. Capital project reimbursements are recognized as contributions from MPC. Expense project reimbursements are recognized as either revenue over the remaining term of the applicable agreement or as an offset to expense. Employee Services Agreements MPLX has various employee services agreements and secondment agreements with MPC under which MPLX reimburses MPC for employee benefit expenses, along with the provision of operational and management services in support of both our Crude Oil and Products Logistics and Natural Gas and NGL Services segments’ operations (“ESA Charges”). Related Party Loan MPLX is party to a loan agreement (the “MPC Loan Agreement”) with MPC. Under the terms of the MPC Loan Agreement, MPC extends loans to MPLX on a revolving basis as requested by MPLX and as agreed to by MPC. The borrowing capacity of the MPC Loan Agreement is $1.5 billion aggregate principal amount of all loans outstanding at any one time. The MPC Loan Agreement was renewed on July 31, 2024 and is now scheduled to expire, and borrowings under the loan agreement are scheduled to mature and become due and payable, on July 31, 2029, provided that MPC may demand payment of all or any portion of the outstanding principal amount of the loan, together with all accrued and unpaid interest and other amounts, if any, at any time prior to maturity. Borrowings under the MPC Loan Agreement bear interest at one-month term SOFR adjusted upward by 0.10 percent plus 1.25 percent or such lower rate as would be applicable to such loans under the MPLX Credit Agreement as discussed in Note 17. There was no activity on the MPC Loan Agreement for the years ended December 31, 2024 and 2023. Activity on the MPC Loan Agreement for the year ended December 31, 2022 was as follows: (In millions, except %) 2022 Borrowings $ 2,989 Weighted average interest rate of borrowings 1.50 % Repayments $ 4,439 Outstanding balance at end of period $ — Related Party Revenue Related party revenue consists primarily of revenue recognized from the commercial agreements with MPC as well as fees charged under operating agreements with MPC or our equity affiliates as outlined above. Certain product sales to MPC and other related parties net to zero within the consolidated financial statements as the transactions are recorded net due to the terms of the agreements under which such product was sold. For the years ended December 31, 2024, 2023 and 2022, these sales totaled $754 million, $739 million and $1,002 million, respectively. Related Party Expenses Related party expenses consist primarily of Omnibus Charges, ESA Charges, and fees paid under the co-location agreements and ground lease agreements as outlined above. Omnibus Charges and ESA Charges are classified as Rental cost of sales - related parties, Purchases - related parties, or General and administrative expenses depending on the nature of the asset or activity with which the costs are associated. Additionally, we also incur costs under agreements for transportation and processing services with certain of our unconsolidated affiliates. In addition to these agreements, MPLX purchases products from MPC, makes payments to MPC in its capacity as general contractor to MPLX, and has certain rent and lease agreements with MPC. For the years ended December 31, 2024, 2023 and 2022, General and administrative expenses incurred from MPC totaled $289 million, $262 million and $235 million, respectively. Some charges incurred under the omnibus and employee service agreements are related to engineering services and are associated with assets under construction. These charges are added to Property, plant and equipment, net on the Consolidated Balance Sheets. For 2024, 2023 and 2022, these charges totaled $182 million, $94 million and $70 million, respectively. Related Party Assets and Liabilities Assets and liabilities with related parties appearing in the Consolidated Balance Sheets are detailed in the table below. This table identifies the various components of related party assets and liabilities, including those associated with leases (see Note 21 for additional information) and deferred revenue. December 31, (In millions) 2024 2023 Current assets - related parties Receivables $ 620 $ 587 Lease receivables 204 149 Prepaid 5 5 Other 1 7 Total 830 748 Noncurrent assets - related parties Long-term lease receivables 677 789 Right of use assets 226 227 Unguaranteed residual asset 189 126 Long-term receivables 28 19 Total 1,120 1,161 Current liabilities - related parties MPC loan agreement and other payables (1) 288 278 Deferred revenue 106 81 Operating lease liabilities 2 1 Total 396 360 Long-term liabilities - related parties Long-term operating lease liabilities 224 226 Long-term deferred revenue 110 99 Total $ 334 $ 325 (1) There were no borrowings outstanding on the MPC Loan Agreement as of December 31, 2024 or December 31, 2023. Other Related Party Transactions From time to time, MPLX may also sell to or purchase from related parties, assets and inventory at the lesser of average unit cost or net realizable value.

Equity

Equity	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Equity	Equity Units Outstanding MPLX had 1,017,142,290 common units outstanding as of December 31, 2024. Of that number, 647,415,452 were owned by MPC. The changes in the number of common units during the years ended December 31, 2022, 2023, and 2024 are summarized below: (In units) Common Units Balance at December 31, 2021 1,016,178,378 Unit-based compensation awards 190,529 Units redeemed in unit repurchase program (15,348,291) Balance at December 31, 2022 1,001,020,616 Unit-based compensation awards 196,428 Conversion of Series A preferred units (1) 2,281,831 Balance at December 31, 2023 1,003,498,875 Unit-based compensation awards 141,985 Conversion of Series A preferred units (1) 21,078,998 Units redeemed in unit repurchase program (7,577,568) Balance at December 31, 2024 1,017,142,290 (1) Certain Series A preferred unitholders have exercised their rights to convert their Series A preferred units into common units as discussed in Note 9. Unit Repurchase Program On November 2, 2020, MPLX announced the board authorization of a unit repurchase program for the repurchase of up to $1 billion of MPLX’s outstanding common units held by the public, which was exhausted during the fourth quarter of 2022. On August 2, 2022, we announced the board authorization for the repurchase of up to an additional $1 billion of MPLX common units held by the public. This unit repurchase authorization has no expiration date. We may utilize various methods to effect the repurchases, which could include open market repurchases, negotiated block transactions, accelerated unit repurchases, tender offers or open market solicitations for units, some of which may be effected through Rule 10b5-1 plans. The timing and amount of future repurchases, if any, will depend upon several factors, including market and business conditions, and such repurchases may be suspended, discontinued or restarted at any time. Total unit repurchases were as follows for the years ended December 31, 2024, 2023 and 2022: (In millions, except per unit data) 2024 2023 2022 Number of units repurchased 8 — 15 Cash paid for units repurchased (1) $ 326 $ — $ 491 Average cost per unit (1) $ 43.04 $ — $ 31.96 (1) Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period. As of December 31, 2024, we had $520 million remaining under the unit repurchase authorization. Redemption of the Series B Preferred Units On February 15, 2023, MPLX exercised its right to redeem all 600,000 units of 6.875 percent Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the “Series B preferred units”). MPLX paid unitholders the Series B preferred unit redemption price of $1,000 per unit. MPLX made a final cash distribution of $21 million to Series B preferred unitholders on February 15, 2023, in conjunction with the redemption. The changes in the Series B preferred unit balance during 2023 and 2022 are included in the Consolidated Statements of Equity within Series B preferred units. Cash Distributions Total distributions declared for the years ended December 31, 2024, 2023 and 2022 are summarized in the table below. 2024 2023 2022 Distributions per common unit $ 3.613 $ 3.250 $ 2.960 The allocation of total quarterly cash distributions to limited, and preferred unitholders is as follows for the years ended December 31, 2024, 2023 and 2022. The Partnership Agreement sets forth the calculation to be used to determine the amount and priority of cash distributions that the common unitholders and preferred unitholders will receive. MPLX’s distributions are declared subsequent to quarter end; therefore, the following table represents total cash distributions applicable to the period in which the distributions were earned. (In millions) 2024 2023 2022 Common and preferred unit distributions: Common unitholders, includes common units of general partner $ 3,678 $ 3,256 $ 2,980 Series A preferred unit distributions 27 94 88 Series B preferred unit distributions (1) — 5 41 Total cash distributions declared $ 3,705 $ 3,355 $ 3,109 (1) 2023 period includes the portion of the $21 million distribution paid to the Series B preferred unitholders on February 15, 2023 that was earned during the period prior to the redemption. On January 22, 2025, MPLX declared a quarterly cash distribution, based on the results of the fourth quarter of 2024, totaling $972 million, or $0.9565 per common unit. This rate was also received by Series A preferred unitholders. These distributions were paid on February 14, 2025 to unitholders of record on February 3, 2025.

Net Income Per Limited Partner

Net Income Per Limited Partner Unit	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Net Income Per Limited Partner Unit [Text Block]	Net Income Per Limited Partner Unit Net income per unit applicable to common limited partner units is computed by dividing net income attributable to MPLX LP less income allocated to participating securities by the weighted average number of common units outstanding. During the years ended December 31, 2024, 2023 and 2022, MPLX had participating securities consisting of common units, certain equity-based compensation awards, Series A preferred units, and Series B preferred units and also had dilutive potential common units consisting of certain equity-based compensation awards. Potential common units omitted from the diluted earnings per unit calculation for the years ended December 31, 2024, 2023 and 2022, were less than 1 million. (In millions, except per unit data) 2024 2023 2022 Net income attributable to MPLX LP (1) : $ 4,317 $ 3,928 $ 3,944 Less: Distributions declared on Series A preferred units 27 94 88 Distributions declared on Series B preferred units — 5 41 Distributions declared on other participating securities 2 — — Undistributed earnings allocated to participating securities 7 16 24 Impact of redemption of Series B preferred units — 5 — Net Income available to common unitholders $ 4,281 $ 3,808 $ 3,791 Weighted average units outstanding: Basic 1,016 1,001 1,010 Diluted 1,017 1,002 1,010 Net income attributable to MPLX LP per limited partner unit: Basic $ 4.21 $ 3.80 $ 3.75 Diluted $ 4.21 $ 3.80 $ 3.75 (1) Allocation of net income attributable to MPLX LP assumes all earnings for the period have been distributed based on the distribution priorities applicable to the period.

Redeemable Preferred Units

Redeemable Preferred Units	12 Months Ended
	Dec. 31, 2024
Redeemable Preferred Units Disclosure [Abstract]
Preferred Stock	Series A Preferred Units 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 for a cash purchase price of $32.50 per unit. The aggregate net proceeds of approximately $984 million from the sale of the Series A preferred units were used for capital expenditures, repayment of debt and general business purposes. Preferred Unit Distribution Rights The Series A preferred units rank senior to all common units and pari passu with all Series B preferred units with respect to distributions and rights upon liquidation. The holders of the Series A preferred units are entitled to receive, when and if declared by the board, a quarterly distribution equal to the greater of $0.528125 per unit or the amount of distributions they would have received on an as converted basis, including any supplemental distributions made to common unitholders. On January 22, 2025, MPLX declared a quarterly cash distribution of $0.9565 per common unit for the fourth quarter of 2024. Holders of the Series A preferred units received the common unit rate in lieu of the lower $0.528125 base amount. The holders may convert their Series A preferred units into common units at any time, in full or in part, subject to minimum conversion amounts and conditions. After the fourth anniversary of the issuance date, MPLX may convert the Series A preferred units into common units at any time, in whole or in part, subject to certain minimum conversion amounts and conditions, if the closing price of MPLX common units is greater than $48.75 for the 20-day trading period immediately preceding the conversion notice date. The conversion rate for the Series A preferred units shall be the quotient of (a) the sum of (i) $32.50, plus (ii) any unpaid cash distributions on the applicable preferred unit, divided by (b) $32.50, subject to adjustment for unit distributions, unit splits and similar transactions. The holders of the Series A preferred units are entitled to vote on an as-converted basis with the common unitholders and have certain other class voting rights with respect to any amendment to the MPLX partnership agreement that would adversely affect any rights, preferences or privileges of the preferred units. In addition, upon certain events involving a change of control, the holders of preferred units may elect, among other potential elections, to convert their Series A preferred units to common units at the then applicable change of control conversion rate. Preferred Units Outstanding During the years ended December 31, 2024 and December 31, 2023, certain Series A preferred unitholders exercised their rights to convert their Series A preferred units into 21 million common units and 2 million common units, respectively. Approximately 6 million Series A preferred units were outstanding as of December 31, 2024. On February 11, 2025, MPLX exercised its right to convert the remaining outstanding Series A preferred units into common units in accordance with the conversion provision discussed above. Financial Statement Presentation The Series A preferred units are considered redeemable securities under GAAP due to the existence of redemption provisions upon a deemed liquidation event, which is outside MPLX’s control. Therefore, they are presented as temporary equity in the mezzanine section of the Consolidated Balance Sheets. The Series A preferred units have been recorded at their issuance date fair value, net of issuance costs. Income allocations increase the carrying value and declared distributions decrease the carrying value of the Series A preferred units. As the Series A preferred units are not currently redeemable and not probable of becoming redeemable, adjustment to the initial carrying amount is not necessary and would only be required if it becomes probable that the Series A preferred units would become redeemable. For a summary of changes in the redeemable preferred balance for the years ended December 31, 2024, 2023 and 2022, see the Consolidated Statements of Equity.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Segment Information	MPLX’s chief operating decision maker (“CODM”) is the chief executive officer of its general partner. The CODM reviews MPLX’s discrete financial information, makes operating decisions, assesses financial performance and allocates resources on a product-based value chain basis. As discussed in Note 1, we renamed and modified the composition of our segments in the fourth quarter of 2024. The segment realignment is presented for the year ended December 31, 2024, with prior periods recast for comparability. See Note 1 for additional details. MPLX has two reportable segments: Crude Oil and Products Logistics and Natural Gas and NGL Services. Each of these segments is organized and managed based upon the product-based value chain each supports. • Crude Oil and Products Logistics – gathers, transports, stores and distributes crude oil, refined products, other hydrocarbon-based products and renewables. Also includes the operation of refining logistics, fuels distribution and inland marine businesses, terminals, rail facilities and storage caverns. • Natural Gas and NGL Services – gathers, processes and transports natural gas; and transports, fractionates, stores and markets NGLs. Our CODM evaluates the performance of our segments using Segment Adjusted EBITDA. The CODM uses adjusted EBITDA by segment results when making decisions about allocating capital and personnel as a part of the annual business plan process and ongoing monitoring of performance. Amounts included in net income and excluded from Segment Adjusted EBITDA include: (i) depreciation and amortization; (ii) net interest and other financial costs; (iii) income/(loss) from equity method investments; (iv) distributions and adjustments related to equity method investments; (v) impairment expense; (vi) noncontrolling interests; and (vii) other adjustments as applicable. These items are either: (i) believed to be non-recurring in nature; (ii) not believed to be allocable or controlled by the segment; or (iii) are not tied to the operational performance of the segment. Assets by segment are not a measure used to assess the performance of the Partnership by our CODM and thus are not reported in our disclosures. The tables below present information about our reportable segments: (In millions) 2024 2023 2022 Crude Oil and Products Logistics Service revenue $ 4,543 $ 4,335 $ 4,057 Rental income 882 857 803 Product related revenue 18 18 19 Sales-type lease revenue 475 500 465 Income from equity method investments 269 270 197 Other income 152 68 57 Total segment revenues and other income (1) 6,339 6,048 5,598 Operating expenses 2,097 2,006 1,937 Other segment items (2) (133) (92) (100) Segment Adjusted EBITDA (3) 4,375 4,134 3,761 Capital expenditures 482 414 325 Investments in unconsolidated affiliates (4) 93 8 63 Natural Gas and NGL Services Service revenue 2,407 2,189 2,056 Rental income 222 208 287 Product related revenue 2,221 2,191 2,792 Sales-type lease revenue 136 136 62 Income from equity method investments (5) 533 330 279 Other income (6) 75 179 539 Total segment revenues and other income (1) 5,594 5,233 6,015 Purchased product costs 1,561 1,598 2,063 Operating expenses 1,704 1,564 1,472 Other segment items (2) (60) (64) 466 Segment Adjusted EBITDA (3) 2,389 2,135 2,014 Capital expenditures 568 605 528 Investments in unconsolidated affiliates (4) $ 143 $ 90 $ 154 (1) Within the total segment revenues and other income amounts presented above, third party revenues for the Crude Oil and Products Logistics segment were $746 million, $701 million and $574 million for the years ended December 31, 2024, 2023 and 2022, respectively. Third party revenues for the Natural Gas and NGL Services segment were $5,297 million, $4,902 million and $5,748 million for the years ended December 31, 2024, 2023 and 2022, respectively. (2) Other segment items in the Crude Oil and Products Logistics segment include income from equity method investments, distributions and adjustments related to equity method investments, equity-based compensation and other miscellaneous items. Other segment items in the Natural Gas and NGL Services segment include income from equity method investments, distributions and adjustments related to equity method investments, gains on sales-type leases and equity method investments, unrealized derivative gain/loss and other miscellaneous items. (3) See below for the reconciliation from Segment Adjusted EBITDA to Net income. (4) Investments in unconsolidated affiliates for the Crude Oil and Products Logistics segment include contributions of $92 million and $60 million for the years ended December 31, 2024 and 2022, respectively, to Dakota Access to fund our share of debt repayments by the joint venture and exclude $18 million related to the acquisition of additional interest in Wink to Webster Pipeline LLC for the year ended December 31, 2024. Investments in unconsolidated affiliates for the Natural Gas and NGL Services segment exclude $210 million related to the acquisition of additional interests in BANGL, LLC for the year ended December 31, 2024. (5) Includes a $151 million gain related to the dilution of ownership interest in connection with the Whistler Joint Venture Transaction in 2024. (6) Includes a $92 million gain on remeasurement of our existing equity investment in Torñado in conjunction with the purchase of the remaining joint venture interest in 2023. Includes a $509 million gain on a lease reclassification for the year ended December 31, 2022. See Note 21 in the Consolidated Financial Statements for additional information. The table below provides a reconciliation of Segment Adjusted EBITDA for reportable segments to Net income. (In millions) 2024 2023 2022 Reconciliation to Net income: Crude Oil and Products Logistics Segment Adjusted EBITDA $ 4,375 $ 4,134 $ 3,761 Natural Gas and NGL Services Segment Adjusted EBITDA 2,389 2,135 2,014 Total reportable segments 6,764 6,269 5,775 Depreciation and amortization (1) (1,283) (1,213) (1,230) Net interest and other financial costs (921) (923) (925) Income from equity method investments 802 600 476 Distributions/adjustments related to equity method investments (928) (774) (652) Gain on sales-type leases and equity method investments — 92 509 Adjusted EBITDA attributable to noncontrolling interests 44 42 38 Garyville incident response costs (2) — (16) — Other (3) (121) (111) (13) Net income $ 4,357 $ 3,966 $ 3,978 (1) Depreciation and amortization attributable to Crude Oil and Products Logistics was $526 million, $530 million and $515 million for the years ended December 31, 2024, 2023 and 2022, respectively. Depreciation and amortization attributable to Natural Gas and NGL Services was $757 million, $683 million and $715 million for the years ended December 31, 2024, 2023 and 2022, respectively. (2) In August 2023, a naphtha release and resulting fire occurred at our Garyville Tank Farm resulting in the loss of four storage tanks with a combined shell capacity of 894 thousand barrels. We incurred $16 million of incident response costs, net of insurance recoveries, during the year ended December 31, 2023. (3) Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.

Major Customers and Concentrati

Major Customers and Concentration of Credit Risk	12 Months Ended
	Dec. 31, 2024
Risks and Uncertainties [Abstract]
Major Customers and Concentration of Credit Risk	Major Customers and Concentration of Credit Risk The table below shows, by segment, the percentage of total revenues and other income with MPC which is our most significant customer and our largest concentration of credit risk. 2024 2023 2022 Total revenues and other income (1) Crude Oil and Products Logistics 88 % 88 % 90 % Natural Gas and NGL Services 4 % 5 % 4 % Total 49 % 50 % 47 % (1) The percent calculations for the year ended December 31, 2024 exclude a gain of $151 million related to the dilution of ownership interest in connection with the Whistler Joint Venture Transaction. The percent calculations for the year ended December 31, 2023 exclude a $92 million gain associated with the remeasurement of its existing equity investment in Torñado. The percent calculations for the year ended December 31, 2022 exclude a $509 million gain on a lease reclassification. Revenue from the sale of products purchased after services are provided is reported as Product sales on the Consolidated Statements of Income and recognized on a gross basis, as MPLX takes control of the product and is the principal in the transaction. For the year ended December 31, 2023, revenues with one customer primarily related to these NGL transactions accounted for approximately 10 percent of our total revenues and other income, respectively. MPLX has a concentration of trade receivables due from customers in the same industry: MPC, integrated oil companies, natural gas exploration and production companies, independent refining companies and other pipeline companies. These concentrations of customers may impact MPLX’s overall exposure to credit risk as they may be similarly affected by changes in economic, regulatory and other factors. MPLX manages its exposure to credit risk through credit analysis, credit limit approvals and monitoring procedures; and for certain transactions, it may request letters of credit, prepayments or guarantees.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2024
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following: December 31, (In millions) 2024 2023 NGLs $ 5 $ 8 Line fill 18 15 Spare parts, materials and supplies 157 136 Total inventories $ 180 $ 159

Property, Plant, and Equipment

Property, Plant, and Equipment	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure	Property, Plant and Equipment Property, plant and equipment with associated accumulated depreciation is shown below: Estimated December 31, (In millions) 2024 2023 Crude Oil and Products Logistics Pipelines 15 - 50 years $ 6,627 $ 6,455 Refining logistics 15 - 20 years 1,867 1,818 Terminals 15 - 40 years 1,726 1,651 Marine 15 - 20 years 1,149 1,100 Land, building and other 5 - 60 years 1,619 1,609 Construction-in-progress 201 146 Total Crude Oil and Products Logistics property, plant and equipment 13,189 12,779 Natural Gas and NGL Services Gathering and transportation 5 - 40 years 7,789 7,484 Processing and fractionation 10 - 40 years 6,611 6,203 Land, building and other 5 - 40 years 541 525 Construction-in-progress 274 394 Total Natural Gas and NGL Services property, plant and equipment 15,215 14,606 Total property, plant and equipment 28,404 27,385 Less accumulated depreciation 9,250 8,121 Property, plant and equipment, net $ 19,154 $ 19,264 We capitalize interest as part of the cost of major projects during the construction period. Capitalized interest totaled $19 million, $15 million and $9 million for the years ended December 31, 2024, 2023 and 2022, respectively.

Goodwill and Intangibles

Goodwill and Intangibles	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	Goodwill and Intangibles Goodwill MPLX annually evaluates goodwill for impairment as of November 30, as well as whenever events or changes in circumstances indicate it is more likely than not that the fair value of a reporting unit with goodwill is less than its carrying amount. Our reporting units are one level below our operating segments and are determined based on the way in which segment management operates and reviews each operating segment. We have five reporting units, three of which have goodwill allocated to them. For the annual impairment assessment as of November 30, 2024, management performed only a qualitative assessment for two reporting units as we determined it was more likely than not that the fair values of the reporting units exceeded their carrying values. The fair value of the crude gathering reporting unit for which a quantitative assessment was performed was determined based on applying both a discounted cash flow, or income approach, as well as a market approach which resulted in the fair value of the reporting unit exceeding its carrying value by greater than 10 percent. The significant assumptions used to develop the estimate of the fair value under the discounted cash flow method included management’s best estimates of the discount rate of 8.5 percent as well as estimates of future cash flows, which are impacted primarily by producers’ development plans, which impact future volumes and capital requirements. 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 annual goodwill impairment test will prove to be an accurate prediction of the future. The fair value measurements for the individual reporting units represent Level 3 measurements. Total goodwill at December 31, 2024 was $7,645 million and no impairment was recorded as a result of our November 30, 2024 annual goodwill impairment analysis. The changes in carrying amount of goodwill were as follows for the periods presented: (In millions) Crude Oil and Products Logistics Natural Gas and NGL Services Total Gross goodwill as of December 31, 2022 $ 7,645 $ 3,141 $ 10,786 Accumulated impairment losses — (3,141) (3,141) Balance as of December 31, 2022 7,645 — 7,645 Balance as of December 31, 2023 7,645 — 7,645 Balance as of December 31, 2024 7,645 — 7,645 Gross goodwill as of December 31, 2024 7,645 3,141 10,786 Accumulated impairment losses — (3,141) (3,141) Balance as of December 31, 2024 $ 7,645 $ — $ 7,645 Intangible Assets MPLX’s intangible assets are comprised of customer contracts and relationships. Gross intangible assets with accumulated amortization as of December 31, 2024 and 2023 is shown below: December 31, 2024 December 31, 2023 (In millions) Gross Accumulated Amortization (1) Net Gross Accumulated Amortization (1) Net Crude Oil and Products Logistics $ 283 $ (224) $ 59 $ 283 $ (189) $ 94 Natural Gas and NGL Services 1,363 (904) 459 1,365 (805) 560 $ 1,646 $ (1,128) $ 518 $ 1,648 $ (994) $ 654 (1) Amortization expense attributable to the Crude Oil and Products Logistics segment for the years ended December 31, 2024 and 2023 was $35 million and $36 million, respectively. Amortization expense attributable to the Natural Gas and NGL Services segment for the years ended December 31, 2024 and 2023 was $99 million and $92 million, respectively. Estimated future amortization expense related to the intangible assets at December 31, 2024 is as follows: (In millions) 2025 $ 121 2026 112 2027 84 2028 67 2029 16 2030 and thereafter 118 Total $ 518

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Text Block]	Fair Value Measurements Fair Values – Recurring The following table presents the impact on the Consolidated Balance Sheets of MPLX’s financial instruments carried at fair value on a recurring basis as of December 31, 2024 and 2023 by fair value hierarchy level. December 31, 2024 2023 (In millions) Asset Liability Asset Liability Embedded derivatives in commodity contracts (Level 3) Other current assets / Other current liabilities $ — $ 10 $ — $ 11 Other noncurrent assets / Other long-term liabilities — 48 — 50 Total carrying value in Consolidated Balance Sheets $ — $ 58 $ — $ 61 Level 2 instruments include over-the-counter fixed swaps to mitigate the price risk from our sales of propane under certain percent-of-proceeds and keep-whole arrangements. The swap valuations are based on observable inputs in the form of forward prices based on Mont Belvieu propane forward spot prices and contain no significant unobservable inputs. All of our Level 2 instruments were settled during 2024. There were no positions outstanding as of December 31, 2024. Level 3 instruments relate to an embedded derivative liability for a natural gas purchase commitment embedded in a keep-whole processing agreement. The fair value calculation for these Level 3 instruments used significant unobservable inputs including: (1) NGL prices interpolated and extrapolated due to inactive markets ranging from $0.65 to $1.54 per gallon with a weighted average of $0.81 per gallon and (2) a 100 percent probability of renewal for the five Changes in Level 3 Fair Value Measurements The following table is a reconciliation of the net beginning and ending balances recorded for net liabilities classified as Level 3 in the fair value hierarchy. (In millions) 2024 2023 Beginning balance $ (61) $ (61) Unrealized and realized (loss)/gain included in Net Income (1) (10) (11) Settlements 13 11 Ending balance (58) (61) The amount of total loss for the period included in earnings attributable to the change in unrealized gain relating to liabilities still held at end of period $ (7) $ (9) (1) (Loss)/gain on derivatives embedded in commodity contracts are recorded in Purchased product costs Fair Values – Non-recurring Non-recurring fair value measurements and disclosures in 2024 and 2023 relate to acquisitions and other transactions as discussed in Note 4. Non-recurring fair value measurements and disclosures in 2022 relate primarily to MPLX’s sales-type leases as discussed in Note 21. The net investment in sales-type leases is recorded at the estimated fair value of the underlying leased assets at contract modification date. The leased assets were valued using a cost method valuation approach which utilizes Level 3 inputs. Fair Values – Reported We believe the carrying value of our other financial instruments, including cash and cash equivalents, receivables, receivables from related parties, lease receivables, lease receivables from related parties, accounts payable, and payables to related parties, approximate fair value. MPLX’s fair value assessment incorporates a variety of considerations, including the duration of the instruments, MPC’s investment-grade credit rating and the historical incurrence of and expected future insignificance of bad debt expense, which includes an evaluation of counterparty credit risk. The recorded value of the amounts outstanding under the bank revolving credit facility, if any, approximates fair value due to the variable interest rate that approximates current market rates. Derivative instruments are recorded at fair value, based on available market information (see Note 16). The fair value of MPLX’s debt is estimated based on prices from recent trade activity and is categorized in Level 3 of the fair value hierarchy. The following table summarizes the fair value and carrying value of our third-party debt, excluding finance leases and unamortized debt issuance costs: December 31, 2024 2023 (In millions) Fair Value Carrying Value Fair Value Carrying Value Outstanding debt (1) $ 19,574 $ 21,068 $ 19,377 $ 20,547 (1) Any amounts outstanding under the MPC Loan Agreement are not included in the table above, as the carrying value approximates fair value. This balance is reflected in Current liabilities - related parties in the Consolidated Balance Sheets.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments During the year ended December 31, 2024, MPLX entered into commodity contracts that were executed to manage price risk during 2024. All of those positions were settled during 2024, with the associated gains included in the table below. As of December 31, 2024, MPLX had no outstanding commodity contracts beyond the embedded derivative discussed below. Embedded Derivative - MPLX has a natural gas purchase commitment embedded in a keep-whole processing agreement with a producer customer in the Southern Appalachia region expiring in December 2027. The customer has the unilateral option to extend the agreement for one five of the customer exercising its option is determined based on assumptions about the customer’s potential business strategy decision points that may exist at the time they would elect whether to renew the contract. The changes in fair value of this compound embedded derivative are based on the difference between the contractual and index pricing, the probability of the producer customer exercising its option to extend, and the estimated favorability of these contracts compared to current market conditions. The changes in fair value are recorded in earnings through Purchased product costs in the Consolidated Statements of Income. For further information regarding the fair value measurement of derivative instruments, see Note 15. See Note 2 for a discussion of derivatives MPLX may use and the reasons for them. At December 31, 2024 and 2023, the estimated fair value of this contract was a liability of $58 million and $61 million, respectively. As of December 31, 2024 and 2023, there were no derivative assets or liabilities that were offset in the Consolidated Balance Sheets. The impact of MPLX’s derivative contracts not designated as hedging instruments and the location of gains and losses recognized in the Consolidated Statements of Income is summarized below: (In millions) 2024 2023 2022 Product sales Realized gain $ 1 $ 7 $ — Product sales derivative gain 1 7 — Purchased product costs Realized loss (13) (11) (12) Unrealized gain 3 — 47 Purchased product cost derivative (loss)/gain (10) (11) 35 Total derivative (loss)/gain included in Net Income $ (9) $ (4) $ 35

Debt

Debt	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Debt	Debt MPLX’s outstanding borrowings consist of the following: December 31, (In millions) 2024 2023 MPLX LP: Bank revolving credit facility $ — $ — 4.875% senior notes due December 1, 2024 — 1,149 4.000% senior notes due February 15, 2025 500 500 4.875% senior notes due June 1, 2025 1,189 1,189 1.750% senior notes due March 1, 2026 1,500 1,500 4.125% senior notes due March 1, 2027 1,250 1,250 4.250% senior notes due December 1, 2027 732 732 4.000% senior notes due March 15, 2028 1,250 1,250 4.800% senior notes due February 15, 2029 750 750 2.650% senior notes due August 15, 2030 1,500 1,500 4.950% senior notes due September 1, 2032 1,000 1,000 5.000% senior notes due March 1, 2033 1,100 1,100 5.500% senior notes due June 1, 2034 1,650 — 4.500% senior notes due April 15, 2038 1,750 1,750 5.200% senior notes due March 1, 2047 1,000 1,000 5.200% senior notes due December 1, 2047 487 487 4.700% senior notes due April 15, 2048 1,500 1,500 5.500% senior notes due February 15, 2049 1,500 1,500 4.950% senior notes due March 14, 2052 1,500 1,500 5.650% senior notes due March 1, 2053 500 500 4.900% senior notes due April 15, 2058 500 500 Consolidated subsidiaries: MarkWest - 4.875% senior notes, due 2024-2025 11 12 ANDX - 4.250% - 5.200% senior notes, due 2027-2047 31 31 Financing lease obligations (1) 6 6 Total 21,206 20,706 Unamortized debt issuance costs (126) (122) Unamortized discount (132) (153) Amounts due within one year (1,693) (1,135) Total long-term debt due after one year $ 19,255 $ 19,296 (1) See Note 21 for lease information. The following table shows five years of scheduled debt payments, including payments on finance lease obligations, as of December 31, 2024: (In millions) 2025 $ 1,701 2026 1,501 2027 2,001 2028 1,250 2029 $ 750 Credit Agreement MPLX Credit Agreement MPLX’s credit agreement (the “MPLX Credit Agreement”) matures in July 2027 and, among other things, provides for a $2.0 billion unsecured revolving credit facility and letter of credit issuing capacity under the facility of up to $150 million. Letter of credit issuing capacity is included in, not in addition to, the $2.0 billion borrowing capacity. Borrowings under the MPLX Credit Agreement bear interest, at MPLX’s election, at either the Adjusted Term SOFR or the Alternate Base Rate, both as defined in the MPLX Credit Agreement, plus an applicable margin. The borrowing capacity under the MPLX Credit Agreement may be increased by up to an additional $1.0 billion, subject to certain conditions, including the consent of lenders whose commitments would increase. In addition, the maturity date may be extended, for up to two additional one year periods, subject to, among other conditions, the approval of lenders holding the majority of the commitments then outstanding, provided that the commitments of any non-consenting lenders will terminate on the then-effective maturity date. MPLX is charged various fees and expenses in connection with the agreement, including administrative agent fees, commitment fees on the unused portion of the facility and fees with respect to issued and outstanding letters of credit. The applicable margins to the benchmark interest rates and certain fees fluctuate based on the credit ratings in effect from time to time on MPLX’s long-term debt. The MPLX Credit Agreement contains certain representations and warranties, affirmative and restrictive covenants and events of default that MPLX considers 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, including for certain acquisitions and dispositions completed and capital projects undertaken during the relevant period. Other covenants restrict MPLX and/or certain of its subsidiaries from incurring debt, creating liens on our assets and entering into transactions with affiliates. As of December 31, 2024, MPLX was in compliance with the covenants contained in the MPLX Credit Agreement. There were no revolver borrowings or repayments under the MPLX Credit Agreement during the years ended December 31, 2024 and 2023. Senior Notes Interest on each series of MPLX LP, MarkWest and ANDX senior notes outstanding is payable semi-annually in arrears, according to the table below. Senior Notes Interest payable semi-annually in arrears 4.000% senior notes due February 15, 2025 February 15 th and August 15 th 4.875% senior notes due June 1, 2025 June 1 st and December 1 st 1.750% senior notes due March 1, 2026 March 1 st and September 1 st 4.125% senior notes due March 1, 2027 March 1 st and September 1 st 4.250% senior notes due December 1, 2027 June 1 st and December 1 st 4.000% senior notes due March 15, 2028 March 15 th and September 15 th 4.800% senior notes due February 15, 2029 February 15 th and August 15 th 2.650% senior notes due August 15, 2030 February 15 th and August 15 th 4.950% senior notes due September 1, 2032 March 1 st and September 1 st 5.000% senior notes due March 1, 2033 March 1 st and September 1 st 5.500% senior notes due June 1, 2034 June 1 st and December 1 st 4.500% senior notes due April 15, 2038 April 15 th and October 15 th 5.200% senior notes due March 1, 2047 March 1 st and September 1 st 5.200% senior notes due December 1, 2047 June 1 st and December 1 st 4.700% senior notes due April 15, 2048 April 15 th and October 15 th 5.500% senior notes due February 15, 2049 February 15 th and August 15 th 4.950% senior notes due March 14, 2052 March 14 th and September 14 th 5.650% senior notes due March 1, 2053 March 1 st and September 1 st 4.900% senior notes due April 15, 2058 April 15 th and October 15 th On May 20, 2024, MPLX issued $1.65 billion aggregate principal amount of the 5.50 percent senior notes due June 2034 (the “2034 Senior Notes”) in an underwritten public offering. The 2034 Senior Notes were offered at a price to the public of 98.778 percent of par, with interest payable semi-annually in arrears, commencing on December 1, 2024. On December 1, 2024, MPLX used $1,150 million of the net proceeds from the issuance of the 2034 Senior Notes to repay all of (i) MPLX’s outstanding $1,149 million aggregate principal amount of 4.875 percent senior notes due December 2024 and (ii) MarkWest’s outstanding $1 million aggregate principal amount of 4.875 percent senior notes due December 2024. On February 18, 2025, MPLX used the remaining net proceeds from the issuance of the 2034 Senior Notes to repay all of MPLX’s outstanding $500 million aggregate principal amount of 4.000 percent senior notes due February 2025. On February 9, 2023, MPLX issued $1.6 billion aggregate principal amount of notes, consisting of $1.1 billion principal amount of 5.00 percent senior notes due 2033 (the “2033 Senior Notes”) and $500 million principal amount of 5.65 percent senior notes due 2053 (the “2053 Senior Notes”). The 2033 Senior Notes were offered at a price to the public of 99.170 percent of par with interest payable semi-annually in arrears, commencing on September 1, 2023. The 2053 Senior Notes were offered at a price to the public of 99.536 percent of par with interest payable semi-annually in arrears, commencing on September 1, 2023. On February 15, 2023, MPLX used $600 million of the net proceeds to redeem all of the outstanding Series B preferred units. On March 13, 2023, MPLX used the remaining proceeds and cash on hand, to redeem all of MPLX’s and MarkWest’s $1.0 billion aggregate principal amount of 4.50 percent senior notes due July 2023, at par, plus accrued and unpaid interest. The redemption resulted in a loss of $9 million due to the immediate expense recognition of unamortized debt discount and issuance costs, which is included on the Consolidated Statements of Income as Net interest and other financial costs. Subordination of Senior Notes The MPLX senior notes are direct, unsecured unsubordinated obligations of MPLX LP. As such, they rank equally in right of payment with all of MPLX LP’s other unsubordinated debt and are not guaranteed by any of MPLX LP’s subsidiaries. The MPLX notes are effectively junior to MPLX LP’s secured indebtedness, if any, to the extent of the value of the relevant collateral. The MPLX notes are not obligations of any of MPLX’s subsidiaries and are effectively subordinated to all indebtedness and other obligations of such subsidiaries. The MPLX notes may be redeemed, in whole or part, at any time at the option of MPLX at a redemption price specified in the indenture governing the applicable notes, plus accrued and unpaid interest to the redemption date. The indenture governing the MPLX senior notes does not limit the amount of debt that MPLX may issue under the indenture, nor the amount of other debt that MPLX or any of its subsidiaries may issue or guaranty. The ANDX senior notes are non-recourse to MPLX and its subsidiaries other than ANDX, the general partner of ANDX and other subsidiaries, if any, of ANDX that are a co-issuer or guarantor of the ANDX senior notes. The MarkWest senior notes are non-recourse to MPLX and its subsidiaries other than MarkWest, the general partner of MarkWest and other subsidiaries, if any, of MarkWest that are a co-issuer or guarantor of the MarkWest senior notes.

Net Interest and Other Financia

Net Interest and Other Financial Costs	12 Months Ended
	Dec. 31, 2024
Other Income and Expenses [Abstract]
Net Interest and Other Financing Costs	Net Interest and Other Financial Costs Net interest and other financial costs were as follows: (In millions) 2024 2023 2022 Interest expense $ 963 $ 912 $ 852 Other financial costs 72 69 81 Interest income (95) (43) (4) Capitalized interest (19) (15) (9) Related-party interest and other financial costs — — 5 Net interest and other financial costs $ 921 $ 923 $ 925

Revenue

Revenue	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue Disaggregation of Revenue The following tables represent a disaggregation of revenue for each reportable segment for the years ended December 31, 2024, 2023 and 2022: 2024 (In millions) Crude Oil and Products Logistics Natural Gas and NGL Services Total Revenues and other income: Service revenue $ 391 $ 2,379 $ 2,770 Service revenue - related parties 4,152 28 4,180 Service revenue - product related — 357 357 Product sales 5 1,652 1,657 Product sales - related parties 13 212 225 Total revenues from contracts with customers $ 4,561 $ 4,628 9,189 Non-ASC 606 revenue (1) 2,744 Total revenues and other income $ 11,933 2023 (In millions) Crude Oil and Products Logistics Natural Gas and NGL Services Total Revenues and other income: Service revenue $ 369 $ 2,170 $ 2,539 Service revenue - related parties 3,966 19 3,985 Service revenue - product related — 294 294 Product sales 5 1,660 1,665 Product sales - related parties 13 237 250 Total revenues from contracts with customers $ 4,353 $ 4,380 8,733 Non-ASC 606 revenue (1) 2,548 Total revenues and other income $ 11,281 2022 (In millions) Crude Oil and Products Logistics Natural Gas and NGL Services Total Revenues and other income: Service revenue $ 320 $ 2,039 $ 2,359 Service revenue - related parties 3,737 17 3,754 Service revenue - product related — 394 394 Product sales 6 2,213 2,219 Product sales - related parties 13 185 198 Total revenues from contracts with customers $ 4,076 $ 4,848 8,924 Non-ASC 606 revenue (1) 2,689 Total revenues and other income $ 11,613 (1) Non-ASC 606 Revenue includes rental income, sales-type lease revenue, income from equity method investments, and other income. Contract Balances Our receivables are primarily associated with customer contracts. Payment terms vary by product or service type; however, the period between invoicing and payment is not significant. Included within the receivables are balances related to commodity sales on behalf of our producer customers, for which we remit the net sales price back to the producer customers upon completion of the sale. Under certain of our contracts, we recognize revenues in excess of billings which we present as contract assets. Contract assets typically relate to deficiency payments related to minimum volume commitments and aid in construction agreements where the revenue recognized and MPLX’s rights to consideration for work completed exceeds the amount billed to the customer. Contract assets are included in Other current assets and Other noncurrent assets on the Consolidated Balance Sheets. Under certain of our contracts, we receive payments in advance of satisfying our performance obligations, which are recorded as contract liabilities. Contract liabilities, which we present as Deferred revenue and Long-term deferred revenue, typically relate to advance payments for aid in construction agreements and deferred customer credits associated with makeup rights and minimum volume commitments. Related to minimum volume commitments, breakage is estimated and recognized into service revenue in instances where it is probable the customer will not use the credit in future periods. We classify contract liabilities as current or long-term based on the timing of when we expect to recognize revenue. The tables below reflect the changes in ASC 606 contract balances for the years ended December 31, 2024 and 2023: (In millions) Balance at Additions/ (Deletions) Revenue Recognized (1) Balance at Contract assets $ 3 $ — $ (1) $ 2 Long-term contract assets 1 (1) — — Deferred revenue 59 86 (61) 84 Deferred revenue - related parties 47 90 (66) 71 Long-term deferred revenue 344 (29) — 315 Long-term deferred revenue - related parties $ 29 $ 15 $ — $ 44 (In millions) Balance at Additions/ (Deletions) Revenue Recognized (1) Balance at Contract assets $ 21 $ (18) $ — $ 3 Long-term contract assets 1 — — 1 Deferred revenue 57 42 (40) 59 Deferred revenue - related parties 63 86 (102) 47 Long-term deferred revenue 216 128 — 344 Long-term deferred revenue - related parties 25 4 — 29 Long-term contract liabilities $ 2 $ (2) $ — $ — (1) No significant revenue was recognized related to past performance obligations in the current periods. Remaining Performance Obligations The table below includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially unsatisfied) as of December 31, 2024. The amounts presented below are generally limited to fixed consideration from contracts with customers that contain minimum volume commitments. A significant portion of our future contracted revenue is excluded from the amounts presented below in accordance with ASC 606. Variable consideration that is constrained or not required to be estimated as it reflects our efforts to perform is excluded from this disclosure. Additionally, we do not disclose information on the future performance obligations for any contract with an original expected duration of one year or less, or that are terminable by our customer with little or no termination penalties. Potential future performance obligations related to renewals that have not yet been exercised or are not certain of exercise are excluded from the amounts presented below. Revenues classified as Rental income and Sales-type lease revenue are also excluded from this table as they are disclosed in Note 21. (In billions) 2025 $ 2.2 2026 2.0 2027 1.8 2028 0.6 2029 0.3 2030 and thereafter 0.5 Total revenue on remaining performance obligations $ 7.4 As of December 31, 2024, unsatisfied performance obligations included in the Consolidated Balance Sheets are $514 million and will be recognized as revenue as the obligations are satisfied, which is generally expected to occur over the next 19 years. A portion of this amount is not disclosed in the table above as it is deemed variable consideration due to volume variability.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2024
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information (In millions) 2024 2023 2022 Net cash provided by operating activities included: Interest paid (net of amounts capitalized) $ 940 $ 893 $ 813 Income taxes paid 6 7 3 Cash paid for amounts included in the measurement of lease liabilities: Payments on operating leases 71 71 73 Net cash provided by financing activities included: Principal payments under finance lease obligations 1 1 2 Non-cash investing and financing activities: Net transfers of property, plant and equipment (to)/from materials and supplies inventories — (8) (1) ROU assets obtained in exchange for new operating lease obligations 47 21 78 ROU assets obtained in exchange for new finance lease obligations 1 — 1 Book value of equity method investment (1) 4 311 — (1) Represents the book value of MPLX’s equity method investment in OCC in 2024 and Torñado in 2023 prior to MPLX buying out the remaining interest in these entities. See Note 4 for additional information. 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) 2024 2023 2022 Additions to property, plant and equipment $ 1,056 $ 937 $ 806 (Decrease)/Increase in capital accruals (6) 82 47 Total capital expenditures $ 1,050 $ 1,019 $ 853

Leases (Notes)

Leases (Notes)	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Lessee, Operating Leases	Lessee We lease a wide variety of facilities and equipment under leases from third parties, including land and building space, office and field equipment, storage facilities and transportation equipment, while our related party leases primarily relate to ground leases associated with our refining logistics assets. Our remaining lease terms range from less than one The components of lease cost were as follows: 2024 2023 2022 (In millions) Related Party Third Related Third Related Third Components of lease costs: Operating lease costs $ 14 $ 58 $ 14 $ 56 $ 15 $ 61 Finance lease cost: Amortization of ROU assets — 1 — 1 — 1 Interest on lease liabilities — — — — — 1 Total finance lease cost — 1 — 1 — 2 Variable lease cost 4 12 4 10 2 16 Short-term lease cost 1 71 1 61 — 45 Total lease cost $ 19 $ 142 $ 19 $ 128 $ 17 $ 124 Supplemental balance sheet data related to leases were as follows: December 31, 2024 December 31, 2023 (In millions, except % and years) Related Party Third Party Related Party Third Party Operating leases Assets Right of use assets $ 226 $ 273 $ 227 $ 264 Liabilities Operating lease liabilities 2 45 1 45 Long-term operating lease liabilities 224 217 226 211 Total operating lease liabilities $ 226 $ 262 $ 227 $ 256 Weighted average remaining lease term 42 years 8 years 43 years 9 years Weighted average discount rate 5.8 % 4.2 % 5.8 % 4.2 % Finance leases Assets Property, plant and equipment, gross $ 10 $ 10 Less: Accumulated depreciation 5 5 Property, plant and equipment, net 5 5 Liabilities Long-term debt due within one year 1 1 Long-term debt 5 5 Total finance lease liabilities $ 6 $ 6 Weighted average remaining lease term 22 years 20 years Weighted average discount rate 6.0 % 6.0 % As of December 31, 2024, maturities of lease liabilities for operating lease obligations and finance lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows: (In millions) Related Party Operating Third Party Operating Finance 2025 $ 15 $ 55 $ 2 2026 15 48 2 2027 14 40 1 2028 14 37 — 2029 14 30 — 2030 and thereafter 532 97 7 Gross lease payments 604 307 12 Less: Imputed interest 378 45 6 Total lease liabilities $ 226 $ 262 $ 6
Lessee, Finance Leases	Lessee We lease a wide variety of facilities and equipment under leases from third parties, including land and building space, office and field equipment, storage facilities and transportation equipment, while our related party leases primarily relate to ground leases associated with our refining logistics assets. Our remaining lease terms range from less than one The components of lease cost were as follows: 2024 2023 2022 (In millions) Related Party Third Related Third Related Third Components of lease costs: Operating lease costs $ 14 $ 58 $ 14 $ 56 $ 15 $ 61 Finance lease cost: Amortization of ROU assets — 1 — 1 — 1 Interest on lease liabilities — — — — — 1 Total finance lease cost — 1 — 1 — 2 Variable lease cost 4 12 4 10 2 16 Short-term lease cost 1 71 1 61 — 45 Total lease cost $ 19 $ 142 $ 19 $ 128 $ 17 $ 124 Supplemental balance sheet data related to leases were as follows: December 31, 2024 December 31, 2023 (In millions, except % and years) Related Party Third Party Related Party Third Party Operating leases Assets Right of use assets $ 226 $ 273 $ 227 $ 264 Liabilities Operating lease liabilities 2 45 1 45 Long-term operating lease liabilities 224 217 226 211 Total operating lease liabilities $ 226 $ 262 $ 227 $ 256 Weighted average remaining lease term 42 years 8 years 43 years 9 years Weighted average discount rate 5.8 % 4.2 % 5.8 % 4.2 % Finance leases Assets Property, plant and equipment, gross $ 10 $ 10 Less: Accumulated depreciation 5 5 Property, plant and equipment, net 5 5 Liabilities Long-term debt due within one year 1 1 Long-term debt 5 5 Total finance lease liabilities $ 6 $ 6 Weighted average remaining lease term 22 years 20 years Weighted average discount rate 6.0 % 6.0 % As of December 31, 2024, maturities of lease liabilities for operating lease obligations and finance lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows: (In millions) Related Party Operating Third Party Operating Finance 2025 $ 15 $ 55 $ 2 2026 15 48 2 2027 14 40 1 2028 14 37 — 2029 14 30 — 2030 and thereafter 532 97 7 Gross lease payments 604 307 12 Less: Imputed interest 378 45 6 Total lease liabilities $ 226 $ 262 $ 6
Lessor, Operating Leases	Lessor Certain fee-based transportation and storage services agreements with MPC and third parties and certain fee-based natural gas transportation and processing agreements with third parties are accounted for as operating leases under ASC 842. These agreements have remaining terms ranging from less than one year to 11 years with renewal options ranging from one year to five years, with some agreements having multiple renewal options. MPLX did not elect to use the practical expedient to combine lease and non-lease components for lessor arrangements. The tables below represent the portion of the contract allocated to the lease component based on relative standalone selling price. We elected the practical expedient to carry forward historical classification conclusions until a modification of an existing agreement occurs. Once a modification occurs, the amended agreement is required to be assessed under ASC 842, to determine whether a reclassification of the lease is required. Lease revenues included on the Consolidated Statements of Income during 2024, 2023 and 2022 were as follows: 2024 2023 2022 (In millions) Related Party Third Related Party Third Related Party Third Operating leases: Rental income $ 853 $ 251 $ 822 $ 243 $ 763 $ 327 Sales-type leases: Interest income (Sales-type rental revenue - fixed minimum) 455 114 467 114 447 46 Interest income (Revenue from variable lease payments) 20 22 33 22 18 16 Sales-type lease revenue $ 475 $ 136 $ 500 $ 136 $ 465 $ 62 During the third quarter of 2022, the approved expansion of a gathering and compression system triggered the first assessment of the related third-party agreement under ASC 842. Additionally, during the year ended December 31, 2022, we executed amendments to certain related party storage, transportation and terminal service agreements between MPLX and MPC to provide for reimbursements for projects, changes to minimum volume commitments or to extend the term of the agreement. The changes required the embedded leases within these agreements to be reassessed under ASC 842. As a result of these lease assessments, certain leases were reclassified from an operating lease to a sales-type lease. Accordingly, the underlying property, plant and equipment, net, and associated deferred revenue, if any, were derecognized and the present value of the future lease payments and the unguaranteed residual value of the assets were recorded as a net investment in sales-type lease during the respective periods. The following presents the consolidated financial statement impact of related-party and third-party sales-type leases, on commencement or modification date. These transactions, including any related gains recognized in the Consolidated Statements of Income, were non-cash transactions. There were no significant transactions to report for the years ended December 31, 2024 and December 31, 2023. 2022 (In millions) Related Party (1) Third Party (2) Lease receivables $ 87 $ 914 Unguaranteed residual assets 6 63 Property, plant and equipment, net (50) (745) Deferred revenue — 277 Amount recognized on commencement date $ 43 $ 509 (1) The amount recognized on commencement date was recorded as a Contribution from MPC in the Consolidated Statements of Equity given the underlying agreements are between entities under common control. (2) The amount recognized on commencement date was recorded as a gain in Other income in the Consolidated Statements of Income. The following is a schedule of minimum future rental payments to be received on the non-cancellable operating leases as of December 31, 2024: (In millions) Related Party Third Party Total 2025 $ 759 $ 98 $ 857 2026 734 77 811 2027 618 55 673 2028 332 47 379 2029 182 46 228 2030 and thereafter 235 214 449 Total minimum future rentals $ 2,860 $ 537 $ 3,397 Annual minimum undiscounted lease payment receipts under our sales-type leases were as follows as of December 31, 2024: (In millions) Related Party Third Party Total 2025 $ 496 $ 172 $ 668 2026 479 157 636 2027 381 147 528 2028 107 138 245 2029 56 130 186 2030 and thereafter 119 896 1,015 Total minimum future rentals 1,638 1,640 3,278 Less: Imputed interest 757 707 1,464 Lease receivable (1) $ 881 $ 933 $ 1,814 Current lease receivables (2) $ 204 $ 102 $ 306 Long-term lease receivables (3) 677 831 1,508 Unguaranteed residual assets (3) 189 95 284 Total sales-type lease assets $ 1,070 $ 1,028 $ 2,098 (1) This amount does not include the unguaranteed residual assets. (2) The related-party balance is presented in Current assets - related parties and the third-party balance is presented in Receivables, net in the Consolidated Balance Sheets. (3) The related-party balance is presented in Noncurrent assets - related parties and the third-party balance is presented in Other noncurrent assets in the Consolidated Balance Sheets. The following schedule summarizes MPLX’s investment in assets held under operating lease by major classes as of December 31, 2024 and 2023: December 31, (In millions) 2024 2023 Pipelines $ 689 $ 677 Refining logistics 1,430 1,399 Terminals 1,310 1,267 Marine 126 126 Gathering and transportation 86 86 Processing and fractionation 1,039 1,000 Land, building and other 171 165 Total property, plant and equipment 4,851 4,720 Less: accumulated depreciation 2,378 2,124 Property, plant and equipment, net $ 2,473 $ 2,596 Capital expenditures related to assets subject to sales-type lease arrangements were $159 million, $85 million and $72 million for the years ended December 31, 2024, 2023 and 2022, respectively. These amounts are reflected as Additions to property, plant and equipment in the Consolidated Statements of Cash Flows.
Lessor, Sales-type Leases	Lessor Certain fee-based transportation and storage services agreements with MPC and third parties and certain fee-based natural gas transportation and processing agreements with third parties are accounted for as operating leases under ASC 842. These agreements have remaining terms ranging from less than one year to 11 years with renewal options ranging from one year to five years, with some agreements having multiple renewal options. MPLX did not elect to use the practical expedient to combine lease and non-lease components for lessor arrangements. The tables below represent the portion of the contract allocated to the lease component based on relative standalone selling price. We elected the practical expedient to carry forward historical classification conclusions until a modification of an existing agreement occurs. Once a modification occurs, the amended agreement is required to be assessed under ASC 842, to determine whether a reclassification of the lease is required. Lease revenues included on the Consolidated Statements of Income during 2024, 2023 and 2022 were as follows: 2024 2023 2022 (In millions) Related Party Third Related Party Third Related Party Third Operating leases: Rental income $ 853 $ 251 $ 822 $ 243 $ 763 $ 327 Sales-type leases: Interest income (Sales-type rental revenue - fixed minimum) 455 114 467 114 447 46 Interest income (Revenue from variable lease payments) 20 22 33 22 18 16 Sales-type lease revenue $ 475 $ 136 $ 500 $ 136 $ 465 $ 62 During the third quarter of 2022, the approved expansion of a gathering and compression system triggered the first assessment of the related third-party agreement under ASC 842. Additionally, during the year ended December 31, 2022, we executed amendments to certain related party storage, transportation and terminal service agreements between MPLX and MPC to provide for reimbursements for projects, changes to minimum volume commitments or to extend the term of the agreement. The changes required the embedded leases within these agreements to be reassessed under ASC 842. As a result of these lease assessments, certain leases were reclassified from an operating lease to a sales-type lease. Accordingly, the underlying property, plant and equipment, net, and associated deferred revenue, if any, were derecognized and the present value of the future lease payments and the unguaranteed residual value of the assets were recorded as a net investment in sales-type lease during the respective periods. The following presents the consolidated financial statement impact of related-party and third-party sales-type leases, on commencement or modification date. These transactions, including any related gains recognized in the Consolidated Statements of Income, were non-cash transactions. There were no significant transactions to report for the years ended December 31, 2024 and December 31, 2023. 2022 (In millions) Related Party (1) Third Party (2) Lease receivables $ 87 $ 914 Unguaranteed residual assets 6 63 Property, plant and equipment, net (50) (745) Deferred revenue — 277 Amount recognized on commencement date $ 43 $ 509 (1) The amount recognized on commencement date was recorded as a Contribution from MPC in the Consolidated Statements of Equity given the underlying agreements are between entities under common control. (2) The amount recognized on commencement date was recorded as a gain in Other income in the Consolidated Statements of Income. The following is a schedule of minimum future rental payments to be received on the non-cancellable operating leases as of December 31, 2024: (In millions) Related Party Third Party Total 2025 $ 759 $ 98 $ 857 2026 734 77 811 2027 618 55 673 2028 332 47 379 2029 182 46 228 2030 and thereafter 235 214 449 Total minimum future rentals $ 2,860 $ 537 $ 3,397 Annual minimum undiscounted lease payment receipts under our sales-type leases were as follows as of December 31, 2024: (In millions) Related Party Third Party Total 2025 $ 496 $ 172 $ 668 2026 479 157 636 2027 381 147 528 2028 107 138 245 2029 56 130 186 2030 and thereafter 119 896 1,015 Total minimum future rentals 1,638 1,640 3,278 Less: Imputed interest 757 707 1,464 Lease receivable (1) $ 881 $ 933 $ 1,814 Current lease receivables (2) $ 204 $ 102 $ 306 Long-term lease receivables (3) 677 831 1,508 Unguaranteed residual assets (3) 189 95 284 Total sales-type lease assets $ 1,070 $ 1,028 $ 2,098 (1) This amount does not include the unguaranteed residual assets. (2) The related-party balance is presented in Current assets - related parties and the third-party balance is presented in Receivables, net in the Consolidated Balance Sheets. (3) The related-party balance is presented in Noncurrent assets - related parties and the third-party balance is presented in Other noncurrent assets in the Consolidated Balance Sheets. The following schedule summarizes MPLX’s investment in assets held under operating lease by major classes as of December 31, 2024 and 2023: December 31, (In millions) 2024 2023 Pipelines $ 689 $ 677 Refining logistics 1,430 1,399 Terminals 1,310 1,267 Marine 126 126 Gathering and transportation 86 86 Processing and fractionation 1,039 1,000 Land, building and other 171 165 Total property, plant and equipment 4,851 4,720 Less: accumulated depreciation 2,378 2,124 Property, plant and equipment, net $ 2,473 $ 2,596 Capital expenditures related to assets subject to sales-type lease arrangements were $159 million, $85 million and $72 million for the years ended December 31, 2024, 2023 and 2022, respectively. These amounts are reflected as Additions to property, plant and equipment in the Consolidated Statements of Cash Flows.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies MPLX is 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 MPLX has not recorded a liability, MPLX is unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings, discovery or court proceedings. However, the ultimate resolution of some of these contingencies could, individually or in the aggregate, be material. Environmental Matters MPLX is subject to federal, state and local 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. Penalties may be imposed for non-compliance. At December 31, 2024 and 2023, accrued liabilities for remediation totaled $ 15 million 19 million MPLX is involved in environmental enforcement matters arising in the ordinary course of business. While the outcome and impact to MPLX cannot be predicted with certainty, management believes the resolution of these environmental matters will not, individually or collectively, have a material adverse effect on its consolidated results of operations, financial position or cash flows. Other Legal Proceedings In July 2020, Tesoro High Plains Pipeline Company, LLC (“THPP”), a subsidiary of MPLX, received a Notification of Trespass Determination from the Bureau of Indian Affairs (“BIA”) relating to a portion of the Tesoro High Plains Pipeline that crosses the Fort Berthold Reservation in North Dakota. The notification demanded the immediate cessation of pipeline operations and assessed trespass damages of approximately $187 million. After subsequent appeal proceedings and in compliance with a new order issued by the BIA, in December 2020, THPP paid approximately $4 million in assessed trespass damages and ceased use of the portion of the pipeline that crosses the property at issue. In March 2021, the BIA issued an order purporting to vacate the BIA's prior orders related to THPP’s alleged trespass and direct the Regional Director of the BIA to reconsider the issue of THPP’s alleged trespass and issue a new order. In April 2021, THPP filed a lawsuit in the District of North Dakota against the United States of America, the U.S. Department of the Interior and the BIA (collectively, the “U.S. Government Parties”) challenging the March 2021 order purporting to vacate all previous orders related to THPP’s alleged trespass. On February 8, 2022, the U.S. Government Parties filed their answer and counterclaims to THPP’s suit claiming THPP is in continued trespass with respect to the pipeline and seek disgorgement of pipeline profits from June 1, 2013 to present, removal of the pipeline and remediation. On November 8, 2023, the District Court of North Dakota granted THPP’s motion to sever and stay the U.S. Government Parties’ counterclaims. The case will proceed on the merits of THPP’s challenge to the March 2021 order purporting to vacate all previous orders related to THPP’s alleged trespass. THPP continues not to operate that portion of the pipeline that crosses the property at issue. MPLX is 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 MPLX cannot be predicted with certainty, management believes the resolution of these other lawsuits and proceedings will not, individually or collectively, have a material adverse effect on its consolidated financial position, results of operations or cash flows. Guarantees Over the years, MPLX has sold various assets in the normal course of its 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 MPLX to perform upon the occurrence of a triggering event or condition. These guarantees and indemnifications are part of the normal course of selling assets. MPLX is 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. Dakota Access We hold a 9.19 percent indirect interest in Dakota Access, which owns and operates the Bakken Pipeline system. In 2020, the U.S. District Court for the District of Columbia (the “D.D.C.”) ordered the United States Army Corps of Engineers (“Army Corps”), which granted permits and an easement for the Bakken Pipeline system, to prepare an environmental impact statement (“EIS”) relating to an easement under Lake Oahe in North Dakota. The D.D.C. later vacated the easement. The Army Corps issued a draft EIS in September 2023 detailing various options for the easement going forward, including denying the easement, approving the easement with additional measures, rerouting the easement, or approving the easement with no changes. The Army Corps has not selected a preferred alternative, but will make a decision in its final review, after considering input from the public and other agencies. The pipeline remains operational while the Army Corps finalizes its decision which will follow the issuance of the final EIS. According to public statements from Army Corps officials, the EIS is now expected to be issued in 2025. We have entered into a Contingent Equity Contribution Agreement whereby MPLX LP, along with the other joint venture owners in the Bakken Pipeline system, has agreed to make equity contributions to the joint venture upon certain events occurring to allow the entities that own and operate the Bakken Pipeline system to satisfy their senior note payment obligations. The senior notes were issued to repay amounts owed by the pipeline companies to fund the cost of construction of the Bakken Pipeline system. If the vacatur of the easement results in a temporary shutdown of the pipeline, MPLX would have to contribute its 9.19 percent pro rata share of funds required to pay interest accruing on the notes and any portion of the principal that matures while the pipeline is shut down. MPLX also expects to contribute its 9.19 percent pro rata share of any costs to remediate any deficiencies to reinstate the easement and/or return the pipeline into operation. If the vacatur of the easement results in a permanent shutdown of the pipeline, MPLX would have to contribute its 9.19 percent pro rata share of the cost to redeem the bonds (including the one percent redemption premium required pursuant to the indenture governing the notes) and any accrued and unpaid interest. As of December 31, 2024, our maximum potential undiscounted payments under the Contingent Equity Contribution Agreement were approximately $78 million. WPC Parent, LLC MPLX’s maximum exposure to loss for WPC Parent, LLC includes an $82 million commitment to indemnify a joint venture member for our pro rata share of any payments made under a performance guarantee for construction of a pipeline by an equity method investee. Contractual Commitments and Contingencies At December 31, 2024, MPLX’s contractual commitments to acquire property, plant and equipment totaled $128 million. In addition, from time to time and in the ordinary course of business, MPLX and its affiliates provide guarantees of MPLX’s subsidiaries payment and performance obligations in the Natural Gas and NGL Services segment. Certain natural gas processing and gathering arrangements require MPLX to construct new 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 producers 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, 2024, management does not believe there are any indications that MPLX 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. Other Contractual Obligations MPLX executed various third-party transportation, terminalling, and gathering and processing agreements that obligate us to minimum volume, throughput or payment commitments over the remaining terms, which range from less than one year to seven years. After the minimum volume commitments are met in these agreements, MPLX pays additional amounts based on throughput. These agreements may include escalation clauses based on various inflationary indices; however, those potential increases have not been incorporated in minimum fees due under these agreements presented below. The minimum future payments under these agreements as of December 31, 2024 are as follows: (In millions) 2025 $ 166 2026 152 2027 136 2028 125 2029 87 2030 and thereafter 9 Total $ 675

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	During the quarter ended December 31, 2024, no director or officer (as defined in Rule 16a-1(f) promulgated under the Exchange Act) of MPLX adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement” (as each term is defined in Item 408 of Regulation S-K).
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Cybersecurity Risk Management a

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Risk Management and Strategy MPC has processes in place designed to protect our information systems, data, assets, infrastructure and computing environments from cybersecurity threats and risks while maintaining confidentiality, integrity, and availability. These enterprise-wide processes are based upon policies, practices and standards that guide MPC on identifying, assessing, and managing material cybersecurity risks and include, but are not limited to: • placing security limits on physical and network access to our information technology (“IT”) and operating technology (“OT”) systems; • employing internal IT and OT controls designed to detect cybersecurity threats by collecting and analyzing data in MPC’s centralized cybersecurity operations center; • utilizing layers of defensive methodologies designed to facilitate cyber resilience, minimize attack surfaces, and provide flexibility and scalability in MPC’s ability to address cybersecurity risks and threats; • providing cybersecurity threat and awareness training to employees and contractors; • limiting remote network access to our IT and OT network environments; and • assessing our cybersecurity resiliency through various methods, including penetration testing, tabletop exercises with varying scenarios and participants ranging from individuals on our operations teams to executive leadership, and analyzing our corporate cybersecurity incident response plan. MPC applies an enterprise risk management (“ERM”) methodology as established and led by the MPC and MPLX GP executive leadership team and overseen by the Board to identify, assess, and manage enterprise-level risks. MPC’s cybersecurity risk program directly integrates and is intended to align with MPC’s governing ERM program. MPC engages with external resources to contribute to and provide independent evaluation of its cybersecurity practices, including a periodic assessment of its cybersecurity program that is performed by a third party. MPC’s cybersecurity leadership and operational teams monitor cybersecurity threat intelligence and applicable cybersecurity regulatory requirements in a variety of ways, including by communicating with federal agencies, trade associations, service providers, and other miscellaneous third-party resources. MPLX GP’s management team, through consultation with MPC’s Senior Vice President and Chief Digital Officer (“CDO”), Vice President and Chief Information Security Officer (“CISO”), and the MPLX GP Audit Committee of the MPLX GP Board, use the information gathered from these sources to inform long-term cybersecurity investments and strategies which seek to identify cybersecurity threats and protect against, detect, respond to and recover from cybersecurity incidents. The information systems, data, assets, infrastructure, and computing environments of MPC’s third-party service providers are also at risk of cybersecurity incidents. MPC manages third-party service provider cybersecurity risks through contract management, evaluation of applicable security control assessments, and third-party risk assessment processes. As of February 27, 2025, we do not believe that any risks from cybersecurity threats, including as a result of past cybersecurity incidents have had, or are reasonably likely to have, a material adverse effect on the Partnership, including our business strategy, results of operations or financial condition. However, there can be no assurance that MPC’s cybersecurity processes will prevent or mitigate cybersecurity incidents or threats and that efforts will always be successful. It is possible that cybersecurity incidents may occur and could have a material adverse effect on our business strategy, results of operations, or financial condition. See “Business and Operational Risks--We are increasingly dependent on the performance of our information technology systems and those of our third-party business partners and service providers” in Item 1A. Risk Factors of this Annual Report on Form 10-K. Governance The full Board of Directors of MPLX GP oversees enterprise-level risks and has delegated to the Audit Committee of the MPLX GP Board oversight of risks from cybersecurity threats as informed through MPC’s ERM program. MPC’s CDO and CISO are standing members of the ERM committee, comprised of members of senior management, and as part of the committee, report on and evaluate cybersecurity threats and risk management efforts, as communicated to them by way of their direct reports and the larger cybersecurity team. The MPC CDO and CISO are responsible for managing risks from cybersecurity threats. The CDO and CISO provide regular cybersecurity briefings to the MPLX GP Board of Directors including the MPLX GP Audit Committee, with a minimum of two briefings per year and additional briefings as needed. The MPLX GP Audit Committee also has direct access to the CDO and CISO and their management teams for other updates on cybersecurity and information security strategy throughout the year. Additionally, the CDO and CISO, from time to time, meet with members of management to discuss cybersecurity risks, strategy, and threats. MPC’s CISO is responsible for implementing the cybersecurity program which is comprised of Cybersecurity GRC (Governance, Risk & Compliance), Cybersecurity Architecture, Engineering & Operations, and a Cyber Fusion Center that includes Threat Intelligence, Vulnerability Management, & Incident Response. MPC’s CISO has more than 30 years of experience in the oil and gas industry and has held various leadership and strategic roles across IT, software R&D and marketing, including collectively serving as a chief information security officer for seven years at two publicly traded companies. Its CISO also holds an Executive Master in Cybersecurity degree, a Master of Computer Science degree, and undergraduate degrees in both computer science and mathematics. MPC’s CISO works at the direction of MPC’s CDO, who has more than 20 years of executive IT leadership experience and leads the company’s Digital and Information Technology functions that seek to provide innovative, secure, and reliable technology products and services to MPC and its customers. Prior to joining MPC in 2021, its CDO was employed by General Electric Company (“GE”) and its subsidiary companies for over 20 years, holding several executive IT leadership roles with increasing responsibility. He was then named Senior Vice President and Chief Information Officer of Services for parent company GE in 2017 and was later named the Vice President and Chief Information Officer of GE Healthcare. MPC’s CDO holds a Bachelor’s degree in Business Administration, Management and Information Systems.
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	MPC applies an enterprise risk management (“ERM”) methodology as established and led by the MPC and MPLX GP executive leadership team and overseen by the Board to identify, assess, and manage enterprise-level risks. MPC’s cybersecurity risk program directly integrates and is intended to align with MPC’s governing ERM program.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Governance The full Board of Directors of MPLX GP oversees enterprise-level risks and has delegated to the Audit Committee of the MPLX GP Board oversight of risks from cybersecurity threats as informed through MPC’s ERM program. MPC’s CDO and CISO are standing members of the ERM committee, comprised of members of senior management, and as part of the committee, report on and evaluate cybersecurity threats and risk management efforts, as communicated to them by way of their direct reports and the larger cybersecurity team. The MPC CDO and CISO are responsible for managing risks from cybersecurity threats. The CDO and CISO provide regular cybersecurity briefings to the MPLX GP Board of Directors including the MPLX GP Audit Committee, with a minimum of two briefings per year and additional briefings as needed. The MPLX GP Audit Committee also has direct access to the CDO and CISO and their management teams for other updates on cybersecurity and information security strategy throughout the year. Additionally, the CDO and CISO, from time to time, meet with members of management to discuss cybersecurity risks, strategy, and threats. MPC’s CISO is responsible for implementing the cybersecurity program which is comprised of Cybersecurity GRC (Governance, Risk & Compliance), Cybersecurity Architecture, Engineering & Operations, and a Cyber Fusion Center that includes Threat Intelligence, Vulnerability Management, & Incident Response. MPC’s CISO has more than 30 years of experience in the oil and gas industry and has held various leadership and strategic roles across IT, software R&D and marketing, including collectively serving as a chief information security officer for seven years at two publicly traded companies. Its CISO also holds an Executive Master in Cybersecurity degree, a Master of Computer Science degree, and undergraduate degrees in both computer science and mathematics. MPC’s CISO works at the direction of MPC’s CDO, who has more than 20 years of executive IT leadership experience and leads the company’s Digital and Information Technology functions that seek to provide innovative, secure, and reliable technology products and services to MPC and its customers. Prior to joining MPC in 2021, its CDO was employed by General Electric Company (“GE”) and its subsidiary companies for over 20 years, holding several executive IT leadership roles with increasing responsibility. He was then named Senior Vice President and Chief Information Officer of Services for parent company GE in 2017 and was later named the Vice President and Chief Information Officer of GE Healthcare. MPC’s CDO holds a Bachelor’s degree in Business Administration, Management and Information Systems.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	has delegated to the Audit Committee of the MPLX GP Board oversight of risks from cybersecurity threats as informed through MPC’s ERM program.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	MPC’s CDO and CISO are standing members of the ERM committee, comprised of members of senior management, and as part of the committee, report on and evaluate cybersecurity threats and risk management efforts, as communicated to them by way of their direct reports and the larger cybersecurity team. The MPC CDO and CISO are responsible for managing risks from cybersecurity threats. The CDO and CISO provide regular cybersecurity briefings to the MPLX GP Board of Directors including the MPLX GP Audit Committee, with a minimum of two briefings per year and additional briefings as needed. The MPLX GP Audit Committee also has direct access to the CDO and CISO and their management teams for other updates on cybersecurity and information security strategy throughout the year. Additionally, the CDO and CISO, from time to time, meet with members of management to discuss cybersecurity risks, strategy, and threats.
Cybersecurity Risk Role of Management [Text Block]	MPC’s CISO is responsible for implementing the cybersecurity program which is comprised of Cybersecurity GRC (Governance, Risk & Compliance), Cybersecurity Architecture, Engineering & Operations, and a Cyber Fusion Center that includes Threat Intelligence, Vulnerability Management, & Incident Response
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	MPC’s CISO is responsible for implementing the cybersecurity program
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	MPC’s CISO has more than 30 years of experience in the oil and gas industry and has held various leadership and strategic roles across IT, software R&D and marketing, including collectively serving as a chief information security officer for seven years at two publicly traded companies. Its CISO also holds an Executive Master in Cybersecurity degree, a Master of Computer Science degree, and undergraduate degrees in both computer science and mathematics. MPC’s CISO works at the direction of MPC’s CDO, who has more than 20 years of executive IT leadership experience and leads the company’s Digital and Information Technology functions that seek to provide innovative, secure, and reliable technology products and services to MPC and its customers. Prior to joining MPC in 2021, its CDO was employed by General Electric Company (“GE”) and its subsidiary companies for over 20 years, holding several executive IT leadership roles with increasing responsibility. He was then named Senior Vice President and Chief Information Officer of Services for parent company GE in 2017 and was later named the Vice President and Chief Information Officer of GE Healthcare. MPC’s CDO holds a Bachelor’s degree in Business Administration, Management and Information Systems.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	The MPC CDO and CISO are responsible for managing risks from cybersecurity threats. The CDO and CISO provide regular cybersecurity briefings to the MPLX GP Board of Directors including the MPLX GP Audit Committee, with a minimum of two briefings per year and additional briefings as needed. The MPLX GP Audit Committee also has direct access to the CDO and CISO and their management teams for other updates on cybersecurity and information security strategy throughout the year. Additionally, the CDO and CISO, from time to time, meet with members of management to discuss cybersecurity risks, strategy, and threats.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Description of Business and B_2

Description of Business and Basis of Presentation (Policies)	12 Months Ended
	Dec. 31, 2024
Limited Liability Company or Limited Partnership, Business Organization and Operations [Abstract]
Basis of presentation	Basis of Presentation The accompanying consolidated financial statements of MPLX have been prepared in accordance with GAAP. The consolidated financial statements include all majority-owned and controlled subsidiaries. For non-wholly-owned consolidated subsidiaries, the interests owned by third parties have been recorded as Noncontrolling interests on the accompanying Consolidated Balance Sheets. Intercompany accounts and transactions have been eliminated. MPLX’s investments in which MPLX exercises significant influence but does not control and does not have a controlling financial interest are accounted for using the equity method. MPLX’s investments in VIEs, in which MPLX exercises significant influence but does not control and is not the primary beneficiary, are also accounted for using the equity method.

Summary of Principal Accounti_2

Summary of Principal Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Use of estimates	Use of Estimates The preparation of financial statements in accordance with GAAP 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. Actual results could differ materially from those estimates. Estimates are subject to uncertainties due to the levels of subjectivity and judgment necessary to account for highly uncertain matters or the susceptibility of such matters to change and affect items such as valuing identified intangible assets; determining the fair value of derivative instruments; evaluating impairments of long-lived assets, goodwill and equity investments; establishing estimated useful lives for long-lived assets; acquisition accounting; estimating revenues, expense accruals and capital expenditures; valuing AROs; recognizing share-based compensation expense; and determining liabilities, if any, for environmental and legal contingencies.
Revenue recognition	Revenue Recognition Revenue is measured based on consideration specified in a contract with a customer. MPLX recognizes revenue when it satisfies a performance obligation by transferring control over a product or providing services to a customer. MPLX enters into a variety of contract types in order to generate Product sales and Service revenue. MPLX provides services under the following types of arrangements: • Fee-based arrangements – Under fee-based arrangements, MPLX receives fees for the following services: gathering, processing and transportation of natural gas; transportation, fractionation, exchange and storage of NGLs; and transportation, terminalling, storage and distribution of crude oil, refined products, other hydrocarbon-based products, and renewables. The revenue MPLX earns from these arrangements is generally directly related to the volume of natural gas, NGLs, refined products or crude oil that is handled by or flows through MPLX’s systems and facilities and is not normally directly dependent on commodity prices. In certain cases, MPLX’s arrangements provide for minimum volume commitments. Fee-based arrangements are reported as Service revenue on the Consolidated Statements of Income. Revenue is recognized over time as services are performed. In certain instances when specifically stated in the contract terms, MPLX purchases product after fee-based services have been provided. Revenue from the sale of products purchased after services are provided is reported as Product sales on the Consolidated Statements of Income and recognized on a gross basis, as MPLX takes control of the product and is the principal in the transaction. • Percent-of-proceeds arrangements – Under percent-of-proceeds arrangements, MPLX gathers and processes natural gas on behalf of producers; sells the resulting residue gas, condensate and NGLs at market prices; and remits to producers an agreed-upon percentage of the proceeds. In other cases, instead of remitting cash payments to the producer, MPLX delivers an agreed-upon percentage of the residue gas and NGLs to the producer (take-in-kind arrangements) and sells the volumes MPLX retains to third parties or related parties. Revenue is recognized on a net basis when MPLX acts as an agent and does not have control of the gross amount of gas and/or NGLs prior to it being sold. Percent-of-proceeds revenue is reported as Service revenue - product related on the Consolidated Statements of Income. • Keep-whole arrangements – Under keep-whole arrangements, MPLX gathers natural gas from the producer, processes the natural gas and sells the resulting condensate and NGLs to third parties at market prices. Because the extraction of the condensate and NGLs from the natural gas during processing reduces the Btu content of the natural gas, MPLX must either purchase natural gas at market prices for return to producers or make cash payment to the producers equal to the value of the energy content of this natural gas. Certain keep-whole arrangements also have provisions that require MPLX to share a percentage of the keep-whole profits with the producers based on the oil to gas ratio or the NGL to gas ratio. Service revenue - product related is recorded based on the value of the NGLs received on the date the services are performed. Natural gas purchased to return to the producer and shared NGL profits are recorded as a reduction of Service revenue - product related on the Consolidated Statements of Income on the date the services are performed. Sales of NGLs under these arrangements are reported as Product sales on the Consolidated Statements of Income and are reported on a gross basis as MPLX is the principal in the arrangement and controls the product prior to sale. The sale of the NGLs may occur shortly after services are performed at the tailgate of the plant, or after a period of time as determined by MPLX. • Purchase arrangements – Under purchase arrangements, MPLX purchases natural gas at either the wellhead or the tailgate of a plant. MPLX then gathers and delivers the natural gas to pipelines where MPLX may resell the natural gas. Wellhead purchase arrangements represent an arrangement with a supplier and are recorded in Purchased product costs. Often, MPLX earns fees for services performed prior to taking control of the product in these arrangements and Service revenue is recorded for these fees. Revenue generated from the sale of product obtained in tailgate purchase arrangements is reported as Product sales on the Consolidated Statements of Income and is recognized on a gross basis as MPLX purchases and takes control of the product prior to sale and is the principal in the transaction. In many cases, MPLX provides services under contracts that contain a combination of more than one of the arrangements described above. When fees are charged (in addition to product received) under percent-of-proceeds arrangements, keep-whole arrangements or purchase arrangements, MPLX records such fees as Service revenue on the Consolidated Statements of Income. The terms of MPLX’s contracts vary based on gas quality conditions, the competitive environment when the contracts are signed, and customer requirements. Performance obligations are determined based on the specific terms of the arrangements, economics of the geographical regions, and the services offered and whether they are deemed distinct. MPLX allocates the consideration earned between the performance obligations based on the stand-alone selling price when multiple performance obligations are identified. Revenue from MPLX’s service arrangements will generally be recognized over time as the performance obligation is satisfied as services are provided. MPLX has elected to use the output measure of progress to recognize revenue based on the units delivered, processed or transported. The transaction price may have fixed components related to minimum volume commitments and variable components, which are primarily dependent on volumes. Variable consideration will generally not be estimated at contract inception as the transaction price is specifically allocable to the services provided each period. In instances in which tiered pricing structures do not reflect our efforts to perform, MPLX will estimate variable consideration at contract inception. Product sales will be recognized at a point in time when control of the product transfers to the customer. Minimum volume commitments may create contract liabilities if current period payments can be used for future services. If a customer fails to meet its minimum committed volumes, it owes MPLX a deficiency payment based on the terms of the applicable agreement. The deficiency amounts received under these agreements (excluding payments received under agreements classified as sales-type leases) are recorded as Current liabilities or Current liabilities - related parties. In many cases, the customer may then apply the amount of any such deficiency payments as a credit for volumes in excess of its minimum volume commitment in future periods under the terms of the applicable agreements. MPLX recognizes revenue for the deficiency payments when credits are used for volumes in excess of minimum quarterly volume commitments, where it is probable the customer will not use the credit in future periods or upon the expiration of the credits. The use or expiration of the credits is a decrease in Current liabilities or Current liabilities - related parties. Deficiency payments under agreements that have been classified as sales-type leases are recorded as a reduction against the corresponding lease receivable. Amounts billed to customers for shipping and handling, electricity, and other costs to perform services are included in the transaction price as a component of Revenues and other income on the Consolidated Statements of Income. Shipping and handling costs associated with product sales are included in Purchased product costs on the Consolidated Statements of Income. Customers usually pay monthly based on the products purchased or services performed that month. Taxes collected from customers and remitted to the appropriate taxing authority are excluded from revenue. Based on the terms of certain contracts, MPLX is considered to be the lessor under several implicit operating and sales-type lease arrangements in accordance with GAAP. Revenue and costs related to the portion of the revenue earned under these contracts considered to be implicit operating leases are recorded as Rental income and Rental cost of sales, respectively, on the Consolidated Statements of Income. Revenue related to the portion of the revenue earned under these contracts considered to be implicit sales-type lease arrangements is recorded as Sales-type lease revenue on the Consolidated Statements of Income, while related costs are recorded to Cost of revenues or Purchases - related parties.
Revenue and expense accruals	Revenue and Expense Accruals MPLX routinely makes accruals based on estimates for both revenues and expenses due to the timing of compiling billing information, receiving certain third-party information and reconciling MPLX’s records with those of third parties. The delayed information from third parties includes, among other things, actual volumes purchased, transported or sold, adjustments to inventory and invoices for purchases, actual natural gas and NGL deliveries, and other operating expenses. MPLX makes accruals to reflect estimates for these items based on its internal records and information from third parties. Estimated accruals are adjusted when actual information is received from third parties and MPLX’s internal records have been reconciled.
Other taxes	Other Taxes Other taxes primarily include real estate taxes.
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 original maturities of three months or less.
Receivables	Receivables Receivables primarily consist of customer accounts receivable, which are recorded at the invoiced amount and generally do not bear interest. Allowances for doubtful accounts are generally recorded when it becomes probable that the receivable will not be collected and are recorded to bad debt expense. We review the allowance quarterly and past-due balances over 150 days are reviewed individually for collectability. Balances that remain outstanding after reasonable collection efforts have been unsuccessful are written off through a charge to the valuation allowance and a credit to accounts receivable.
Lessee, Leases	Leases Contracts with a term greater than one year that convey the right to direct the use of and obtain substantially all of the economic benefit of an asset are accounted for as right of use (“ROU”) assets and lease liabilities. ROU asset and lease liability balances are recorded at the commencement date at present value of the fixed lease payments using a secured incremental borrowing rate with a maturity similar to the lease term because our leases do not provide implicit rates. We have elected to include both lease and non-lease components in the present value of the lease payments for all lessee asset classes with the exception of our marine and third-party contractor service and equipment leases. The lease component of the payment for the marine and equipment asset classes is determined using a relative standalone selling price. Operating lease expense is recognized on a straight-line basis over the lease term. See Note 21 for additional disclosures about our lease contracts.
Lessor, Leases	As a lessor under ASC 842, MPLX may be required to re-classify existing operating leases to sales-type leases upon modification and related reassessment of the leases. See Note 21 for further information regarding our ongoing evaluation of the impacts of lease reassessments as modifications occur. The net investment in sales-type leases with third parties is recorded within Receivables, net and Other noncurrent assets on the Consolidated Balance Sheets. The net investment in sales-type leases with related parties is recorded within Current assets - related parties and Noncurrent assets - related parties on the Consolidated Balance Sheets. These amounts are comprised of the present value of the sum of the future minimum lease payments representing the value of the lease receivable and the unguaranteed residual value of the leased assets. Management assesses the net investment in sales-type leases for recoverability quarterly.
Inventories	Inventories Inventories consist of materials and supplies to be used in operations, line fill and other NGLs. Cost for materials and supplies are determined primarily using the weighted-average cost method. Inventories are valued at the lower of cost or net realizable value.
Imbalances	Imbalances Within our pipelines and storage assets, we experience volume gains and losses due to pressure and temperature changes, evaporation and variances in meter readings and other measurement methods. Until settled, positive imbalances are recorded as other current assets and negative imbalances are recorded as accounts payable. Positive and negative imbalances are settled in cash, settled by physical delivery of volumes from a different source, or tracked and settled in the future.
Investment in unconsolidated affiliates	Investment in Unconsolidated Affiliates Equity investments in which MPLX exercises significant influence but does not control and is not the primary beneficiary, are accounted for using the equity method and are reported in Equity method investments on the accompanying Consolidated Balance Sheets. This includes entities in which we hold majority ownership, but the minority shareholders have substantive participating rights. 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. Regular evaluation of these investments is appropriate to evaluate any potential need for impairment. MPLX uses evidence of a loss in value to identify if an investment has an other than a temporary decline. Impairments are recorded through Income from equity method investments.
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. Expenditures that extend the useful lives of assets are capitalized. Long-lived assets used in operations are assessed for impairment whenever changes in facts and circumstances indicate that the carrying value of the assets may not be recoverable based on the expected undiscounted future cash flows of an asset group. For purposes of impairment evaluation, long-lived assets must be grouped at the lowest level for which independent cash flows can be identified, which is at least at the segment level and in some cases for similar assets in the same geographic region where cash flows can be separately identified. If the sum of the undiscounted future cash flows from the use of the asset group and its eventual disposition is less than the carrying value of an asset group, an impairment assessment is performed and the excess of the book value over the fair value is recorded as an impairment loss. When items of property, plant and equipment are sold or otherwise disposed of, any gains or losses are reported on the Consolidated Statements of 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.
Goodwill and Intangibles	Goodwill and Intangibles 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 at the reporting unit level 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. If we determine, based on a qualitative assessment, that it is not more likely than not that a reporting unit’s fair value is less than its carrying amount, no further impairment testing is required. If we do not perform a qualitative assessment or if that assessment indicates that further impairment testing is required, the fair value of each reporting unit is determined using an income and market approach which is compared to the carrying value of the reporting unit. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss would be recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit. The fair value under the income approach is calculated using the expected present value of future cash flows method. Significant assumptions used in the cash flow forecasts include future volumes, discount rates, and future capital requirements. See Note 14 for further details. 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.
Environmental costs	Environmental Costs Environmental expenditures for additional equipment that mitigates or prevents future contamination or improves environmental safety or efficiency of the existing assets are capitalized. 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 the 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 An ARO is a legal obligation associated with the retirement of tangible long-lived assets that generally result from the acquisition, construction, development or normal operation of the asset. The fair value of AROs is recognized in the period in which the obligations are incurred, if a reasonable estimate of fair value can be made, and added to the carrying amount of the associated asset. This additional carrying amount is then depreciated over the life of the asset. The liability is determined using a credit adjusted risk free interest rate and increases due to the passage of time based on the time value of money until the obligation is settled. AROs have not been recognized for certain 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. As of December 31, 2024 and 2023, MPLX’s asset retirement obligation was $41 million and $39 million, respectively, and is included on the balance sheet within Other long-term liabilities.
Derivative instruments	Derivative Instruments MPLX may use commodity derivatives to economically hedge a portion of its exposure to commodity price risk. All derivative instruments (including derivatives embedded in other contracts) are recorded at fair value. MPLX discloses the fair value of all derivative instruments under the captions Other current assets, Other noncurrent assets, Other current liabilities and Other long-term liabilities on the Consolidated Balance Sheets. Certain commodity derivative positions are governed by master netting arrangements and are reflected on the consolidated balance sheets on a net basis by counterparty. We make a distinction between realized or unrealized gains and losses on derivatives. During the period when a derivative contract is outstanding, changes in the fair value of the derivative are recorded as an unrealized gain or loss. When a derivative contract matures or is settled, the previously recorded unrealized gain or loss is reversed, and the realized gain or loss of the contract is recorded. Changes in the fair value of derivative instruments are reported on the Consolidated Statements of Income in accounts related to the item whose value or cash flows are being managed. Derivative instruments are marked to market through Product sales and Purchased product costs on the Consolidated Statements of Income. During the years ended December 31, 2024, 2023 and 2022, MPLX did not elect hedge accounting for any derivatives. MPLX has historically elected the normal purchases and normal sales designation for certain contracts related to the physical purchase of electric power and the sale of most commodities.
Fair value measurement	Fair Value Measurement Financial assets and liabilities recorded at fair value in the Consolidated Balance Sheets are categorized based upon the fair value hierarchy established by GAAP, which classifies the inputs used to measure fair value into Level 1, Level 2 or Level 3. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The methods and assumptions utilized may produce a fair value that may not be realized in future periods upon settlement. Furthermore, while MPLX believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. For further discussion, see Note 15.
Equity-based compensation arrangements	Equity-Based Compensation Arrangements MPLX issues phantom units under the MPLX LP 2018 Incentive Compensation Plan. A phantom unit entitles the grantee a right to receive a common unit upon the issuance of the phantom unit. The fair value of phantom unit awards granted to employees and non-management directors is based on the fair market value of MPLX LP common units on the date of grant. The fair value of the units awarded is amortized into earnings using a straight-line amortization schedule over the period of service corresponding with the vesting period. For phantom units that vest immediately and are not forfeitable, equity-based compensation expense is recognized at the time of grant. To satisfy common unit awards, MPLX may issue new common units, acquire common units in the open market or use common units already owned by the general partner.
Income Tax	Income Taxes MPLX is not a taxable entity for United States federal income tax purposes or for the majority of the states that impose an income tax. Taxes on MPLX’s net income generally are borne by its partners through the allocation of taxable income. MPLX’s taxable income or loss, which may vary substantially from the net income or loss reported on the Consolidated Statements of Income, is includable in the federal income tax returns of each partner. MPLX and certain legal entities are, however, taxable entities under certain state jurisdictions. MPLX accounts for income taxes under the asset and liability method. Deferred income taxes are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis, capital loss carryforwards and net operating loss and credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of any tax rate change on deferred taxes is recognized as tax expense/(benefit) from continuing operations in the period that includes the enactment date of the tax rate change. Realizability of deferred tax assets is assessed and, if not more likely than not, a valuation allowance is recorded to reflect the deferred tax assets at net realizable value as determined by management. All deferred tax balances are classified as long-term in the accompanying Consolidated Balance Sheets. All changes in the tax bases of assets and liabilities are allocated among operations and items charged or credited directly to equity.
Distributions	Distributions In preparing the Consolidated Statements of Equity, net income attributable to MPLX LP is allocated to preferred unitholders based on a fixed distribution schedule, as discussed in Notes 7 and 9, and subsequently allocated to the limited partner unitholders. Distributions, although earned, are not accrued as a liability until declared. The allocation of net income attributable to MPLX LP for purposes of calculating net income per limited partner unit is described below.
Net income per limited partner unit	Net Income Per Limited Partner Unit MPLX uses the two-class method when calculating the net income per unit applicable to limited partners, because there is more than one class of participating security. The classes of participating securities include common units, preferred units and certain equity-based compensation awards. Net income attributable to MPLX LP is allocated to the unitholders differently for preparation of the Consolidated Statements of Equity and the calculation of net income per limited partner unit. In preparing the Consolidated Statements of Equity, net income attributable to MPLX LP is allocated to preferred unitholders based on a fixed distribution schedule and subsequently allocated to remaining unitholders in accordance with their respective ownership percentages. The allocation of net income attributable to MPLX LP for purposes of calculating net income per limited partner unit is described in Note 8. In preparing net income per limited partner units, during periods in which a net loss attributable to MPLX is reported or periods in which the total distributions exceed the reported net income attributable to MPLX’s unitholders, the amount allocable to certain equity-based compensation awards is based on actual distributions to the equity-based compensation awards. Diluted earnings per unit is calculated by dividing net income attributable to MPLX’s common unitholders, after deducting amounts allocable to other participating securities, by the weighted average number of common units and potential common units outstanding during the period. Potential common units are excluded from the calculation of diluted earnings per unit during periods in which net income attributable to MPLX’s unitholders, after deducting amounts that are allocable to the outstanding equity-based compensation awards and preferred units, is a loss, as the impact would be anti-dilutive.
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. Any excess or deficit of the purchase consideration when compared to the fair value of the net tangible assets acquired, if any, is recorded as goodwill or gain from a bargain purchase. Depending on the nature of the transaction, management may engage an independent valuation specialist to assist with the determination of fair value of the assets acquired, liabilities assumed, noncontrolling interests, if any, and goodwill, based on recognized business valuation methodologies. An income, market or cost valuation method may be utilized to estimate the fair value of the assets acquired, liabilities assumed, and noncontrolling interests, 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 volumes, certain commodity prices, 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. 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, MPLX will record any material adjustments to the initial estimate based on new information obtained that would have existed as of the acquisition date. Any adjustment that arises from information obtained that did not exist as of the date of the acquisition will be recorded in the period of the adjustment. Acquisition-related costs are expensed as incurred in connection with each business combination. Acquisitions in which the company or business being acquired by MPLX had an existing relationship with MPC may result in the transaction being considered a transfer between entities under common control. In these situations, MPLX records the assets acquired and liabilities assumed on its consolidated balance sheets at MPC’s historical carrying value. For the acquiring entity, transfers of businesses between entities under common control require prior periods to be retrospectively adjusted for those dates that the entity was under common control.

Investments and Noncontrollin_2

Investments and Noncontrolling Interests (Tables)	12 Months Ended
	Dec. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	The following table presents MPLX’s equity method investments at the dates indicated: Ownership as of Carrying value at December 31, December 31, (In millions, except ownership percentages) VIE 2024 2024 2023 Crude Oil and Products Logistics Illinois Extension Pipeline Company, L.L.C. 35% $ 218 $ 228 LOOP LLC 41% 310 314 MarEn Bakken Company LLC (1) 25% 526 449 Other (2) X 541 526 Total Crude Oil and Products Logistics 1,595 1,517 Natural Gas and NGL Services BANGL, LLC (3) 45% 281 63 MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C. X 67% 329 336 MarkWest Utica EMG, L.L.C. X 59% 742 676 Ohio Gathering Company L.L.C. (4) X 35% 470 — Sherwood Midstream LLC X 50% 488 500 WPC Parent, LLC (5) 30% 208 214 Other (2) X 418 437 Total Natural Gas and NGL Services 2,936 2,226 Total $ 4,531 $ 3,743 (1) The investment in MarEn Bakken Company LLC includes our 9.19 percent indirect interest in a joint venture (“Dakota Access”) that owns and operates the Dakota Access Pipeline and Energy Transfer Crude Oil Pipeline projects (collectively referred to as the “Bakken Pipeline system”). (2) Some investments included within Other have also been deemed to be VIEs. (3) In July 2024, we purchased an additional 20 percent ownership interest in BANGL, LLC, increasing our ownership interest to 45 percent, as discussed in Note 4. (4) We acquired a 36 percent direct interest in OGC in the Utica Midstream Acquisition discussed in Note 4. We also hold a 38 percent indirect interest in OGC through our ownership interest in MarkWest Utica EMG, L.L.C. (5) Reflects the dilution of MPLX’s ownership interest in Whistler Pipeline, LLC and the formation of a new entity, WPC Parent, LLC, as discussed in Note 4. The carrying value at December 31, 2024 represents our ownership in WPC Parent, LLC, and the carrying value at December 31, 2023 represents our ownership interest in Whistler Pipeline, LLC.
Investment Company, Nonconsolidated Subsidiary, Summarized Financial Information	Summarized financial information for MPLX’s equity method investments is as follows: (In millions) 2024 2023 2022 Income statement data: Revenues and other income $ 3,594 $ 3,262 $ 2,653 Costs and expenses 1,535 1,331 1,251 Income from operations 2,059 1,930 1,402 Net income 1,631 1,634 1,246 Balance sheet data: Current assets 1,570 1,531 Noncurrent assets 17,927 13,860 Current liabilities 746 979 Noncurrent liabilities 6,711 4,856

Related Party Agreements and _2

Related Party Agreements and Transactions (Tables)	12 Months Ended
	Dec. 31, 2024
Related Party Transactions [Abstract]
Schedule of Short-Term Debt [Table Text Block]	There was no activity on the MPC Loan Agreement for the years ended December 31, 2024 and 2023. Activity on the MPC Loan Agreement for the year ended December 31, 2022 was as follows: (In millions, except %) 2022 Borrowings $ 2,989 Weighted average interest rate of borrowings 1.50 % Repayments $ 4,439 Outstanding balance at end of period $ —
Schedule of Related Party Transactions [Table Text Block]	Related Party Assets and Liabilities Assets and liabilities with related parties appearing in the Consolidated Balance Sheets are detailed in the table below. This table identifies the various components of related party assets and liabilities, including those associated with leases (see Note 21 for additional information) and deferred revenue. December 31, (In millions) 2024 2023 Current assets - related parties Receivables $ 620 $ 587 Lease receivables 204 149 Prepaid 5 5 Other 1 7 Total 830 748 Noncurrent assets - related parties Long-term lease receivables 677 789 Right of use assets 226 227 Unguaranteed residual asset 189 126 Long-term receivables 28 19 Total 1,120 1,161 Current liabilities - related parties MPC loan agreement and other payables (1) 288 278 Deferred revenue 106 81 Operating lease liabilities 2 1 Total 396 360 Long-term liabilities - related parties Long-term operating lease liabilities 224 226 Long-term deferred revenue 110 99 Total $ 334 $ 325 (1) There were no borrowings outstanding on the MPC Loan Agreement as of December 31, 2024 or December 31, 2023. Other Related Party Transactions From time to time, MPLX may also sell to or purchase from related parties, assets and inventory at the lesser of average unit cost or net realizable value.

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Schedule of Stockholders Equity [Table Text Block]	The changes in the number of common units during the years ended December 31, 2022, 2023, and 2024 are summarized below: (In units) Common Units Balance at December 31, 2021 1,016,178,378 Unit-based compensation awards 190,529 Units redeemed in unit repurchase program (15,348,291) Balance at December 31, 2022 1,001,020,616 Unit-based compensation awards 196,428 Conversion of Series A preferred units (1) 2,281,831 Balance at December 31, 2023 1,003,498,875 Unit-based compensation awards 141,985 Conversion of Series A preferred units (1) 21,078,998 Units redeemed in unit repurchase program (7,577,568) Balance at December 31, 2024 1,017,142,290 (1)
Class of Treasury Stock [Table Text Block]	Total unit repurchases were as follows for the years ended December 31, 2024, 2023 and 2022: (In millions, except per unit data) 2024 2023 2022 Number of units repurchased 8 — 15 Cash paid for units repurchased (1) $ 326 $ — $ 491 Average cost per unit (1) $ 43.04 $ — $ 31.96 (1) Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period. As of December 31, 2024, we had $520 million remaining under the unit repurchase authorization.
Dividends Declared	Total distributions declared for the years ended December 31, 2024, 2023 and 2022 are summarized in the table below. 2024 2023 2022 Distributions per common unit $ 3.613 $ 3.250 $ 2.960
Distributions Made to Limited Partner, by Distribution [Table Text Block]	The allocation of total quarterly cash distributions to limited, and preferred unitholders is as follows for the years ended December 31, 2024, 2023 and 2022. The Partnership Agreement sets forth the calculation to be used to determine the amount and priority of cash distributions that the common unitholders and preferred unitholders will receive. MPLX’s distributions are declared subsequent to quarter end; therefore, the following table represents total cash distributions applicable to the period in which the distributions were earned. (In millions) 2024 2023 2022 Common and preferred unit distributions: Common unitholders, includes common units of general partner $ 3,678 $ 3,256 $ 2,980 Series A preferred unit distributions 27 94 88 Series B preferred unit distributions (1) — 5 41 Total cash distributions declared $ 3,705 $ 3,355 $ 3,109 (1) 2023 period includes the portion of the $21 million distribution paid to the Series B preferred unitholders on February 15, 2023 that was earned during the period prior to the redemption.

Net Income (Loss) Per Limited P

Net Income (Loss) Per Limited Partner Unit (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Schedule of Net Income Per Unit, Basic and Diluted [Table Text Block]	(In millions, except per unit data) 2024 2023 2022 Net income attributable to MPLX LP (1) : $ 4,317 $ 3,928 $ 3,944 Less: Distributions declared on Series A preferred units 27 94 88 Distributions declared on Series B preferred units — 5 41 Distributions declared on other participating securities 2 — — Undistributed earnings allocated to participating securities 7 16 24 Impact of redemption of Series B preferred units — 5 — Net Income available to common unitholders $ 4,281 $ 3,808 $ 3,791 Weighted average units outstanding: Basic 1,016 1,001 1,010 Diluted 1,017 1,002 1,010 Net income attributable to MPLX LP per limited partner unit: Basic $ 4.21 $ 3.80 $ 3.75 Diluted $ 4.21 $ 3.80 $ 3.75 (1) Allocation of net income attributable to MPLX LP assumes all earnings for the period have been distributed based on the distribution priorities applicable to the period.	[1]
[1]Allocation of net income attributable to MPLX LP assumes all earnings for the period have been distributed based on the distribution priorities applicable to the period.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	The tables below present information about our reportable segments: (In millions) 2024 2023 2022 Crude Oil and Products Logistics Service revenue $ 4,543 $ 4,335 $ 4,057 Rental income 882 857 803 Product related revenue 18 18 19 Sales-type lease revenue 475 500 465 Income from equity method investments 269 270 197 Other income 152 68 57 Total segment revenues and other income (1) 6,339 6,048 5,598 Operating expenses 2,097 2,006 1,937 Other segment items (2) (133) (92) (100) Segment Adjusted EBITDA (3) 4,375 4,134 3,761 Capital expenditures 482 414 325 Investments in unconsolidated affiliates (4) 93 8 63 Natural Gas and NGL Services Service revenue 2,407 2,189 2,056 Rental income 222 208 287 Product related revenue 2,221 2,191 2,792 Sales-type lease revenue 136 136 62 Income from equity method investments (5) 533 330 279 Other income (6) 75 179 539 Total segment revenues and other income (1) 5,594 5,233 6,015 Purchased product costs 1,561 1,598 2,063 Operating expenses 1,704 1,564 1,472 Other segment items (2) (60) (64) 466 Segment Adjusted EBITDA (3) 2,389 2,135 2,014 Capital expenditures 568 605 528 Investments in unconsolidated affiliates (4) $ 143 $ 90 $ 154 (1) Within the total segment revenues and other income amounts presented above, third party revenues for the Crude Oil and Products Logistics segment were $746 million, $701 million and $574 million for the years ended December 31, 2024, 2023 and 2022, respectively. Third party revenues for the Natural Gas and NGL Services segment were $5,297 million, $4,902 million and $5,748 million for the years ended December 31, 2024, 2023 and 2022, respectively. (2) Other segment items in the Crude Oil and Products Logistics segment include income from equity method investments, distributions and adjustments related to equity method investments, equity-based compensation and other miscellaneous items. Other segment items in the Natural Gas and NGL Services segment include income from equity method investments, distributions and adjustments related to equity method investments, gains on sales-type leases and equity method investments, unrealized derivative gain/loss and other miscellaneous items. (3) See below for the reconciliation from Segment Adjusted EBITDA to Net income. (4) Investments in unconsolidated affiliates for the Crude Oil and Products Logistics segment include contributions of $92 million and $60 million for the years ended December 31, 2024 and 2022, respectively, to Dakota Access to fund our share of debt repayments by the joint venture and exclude $18 million related to the acquisition of additional interest in Wink to Webster Pipeline LLC for the year ended December 31, 2024. Investments in unconsolidated affiliates for the Natural Gas and NGL Services segment exclude $210 million related to the acquisition of additional interests in BANGL, LLC for the year ended December 31, 2024. (5) Includes a $151 million gain related to the dilution of ownership interest in connection with the Whistler Joint Venture Transaction in 2024. (6) Includes a $92 million gain on remeasurement of our existing equity investment in Torñado in conjunction with the purchase of the remaining joint venture interest in 2023. Includes a $509 million gain on a lease reclassification for the year ended December 31, 2022. See Note 21 in the Consolidated Financial Statements for additional information.
Reconciliation of Other Significant Reconciling Items from Segments to Consolidated [Table Text Block]	The table below provides a reconciliation of Segment Adjusted EBITDA for reportable segments to Net income. (In millions) 2024 2023 2022 Reconciliation to Net income: Crude Oil and Products Logistics Segment Adjusted EBITDA $ 4,375 $ 4,134 $ 3,761 Natural Gas and NGL Services Segment Adjusted EBITDA 2,389 2,135 2,014 Total reportable segments 6,764 6,269 5,775 Depreciation and amortization (1) (1,283) (1,213) (1,230) Net interest and other financial costs (921) (923) (925) Income from equity method investments 802 600 476 Distributions/adjustments related to equity method investments (928) (774) (652) Gain on sales-type leases and equity method investments — 92 509 Adjusted EBITDA attributable to noncontrolling interests 44 42 38 Garyville incident response costs (2) — (16) — Other (3) (121) (111) (13) Net income $ 4,357 $ 3,966 $ 3,978 (1) Depreciation and amortization attributable to Crude Oil and Products Logistics was $526 million, $530 million and $515 million for the years ended December 31, 2024, 2023 and 2022, respectively. Depreciation and amortization attributable to Natural Gas and NGL Services was $757 million, $683 million and $715 million for the years ended December 31, 2024, 2023 and 2022, respectively. (2) In August 2023, a naphtha release and resulting fire occurred at our Garyville Tank Farm resulting in the loss of four storage tanks with a combined shell capacity of 894 thousand barrels. We incurred $16 million of incident response costs, net of insurance recoveries, during the year ended December 31, 2023. (3) Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2024
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consist of the following: December 31, (In millions) 2024 2023 NGLs $ 5 $ 8 Line fill 18 15 Spare parts, materials and supplies 157 136 Total inventories $ 180 $ 159

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	Property, plant and equipment with associated accumulated depreciation is shown below: Estimated December 31, (In millions) 2024 2023 Crude Oil and Products Logistics Pipelines 15 - 50 years $ 6,627 $ 6,455 Refining logistics 15 - 20 years 1,867 1,818 Terminals 15 - 40 years 1,726 1,651 Marine 15 - 20 years 1,149 1,100 Land, building and other 5 - 60 years 1,619 1,609 Construction-in-progress 201 146 Total Crude Oil and Products Logistics property, plant and equipment 13,189 12,779 Natural Gas and NGL Services Gathering and transportation 5 - 40 years 7,789 7,484 Processing and fractionation 10 - 40 years 6,611 6,203 Land, building and other 5 - 40 years 541 525 Construction-in-progress 274 394 Total Natural Gas and NGL Services property, plant and equipment 15,215 14,606 Total property, plant and equipment 28,404 27,385 Less accumulated depreciation 9,250 8,121 Property, plant and equipment, net $ 19,154 $ 19,264

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in carrying amount of goodwill were as follows for the periods presented: (In millions) Crude Oil and Products Logistics Natural Gas and NGL Services Total Gross goodwill as of December 31, 2022 $ 7,645 $ 3,141 $ 10,786 Accumulated impairment losses — (3,141) (3,141) Balance as of December 31, 2022 7,645 — 7,645 Balance as of December 31, 2023 7,645 — 7,645 Balance as of December 31, 2024 7,645 — 7,645 Gross goodwill as of December 31, 2024 7,645 3,141 10,786 Accumulated impairment losses — (3,141) (3,141) Balance as of December 31, 2024 $ 7,645 $ — $ 7,645
Schedule of Acquired Finite-Lived Intangible Assets by Major Class	MPLX’s intangible assets are comprised of customer contracts and relationships. Gross intangible assets with accumulated amortization as of December 31, 2024 and 2023 is shown below: December 31, 2024 December 31, 2023 (In millions) Gross Accumulated Amortization (1) Net Gross Accumulated Amortization (1) Net Crude Oil and Products Logistics $ 283 $ (224) $ 59 $ 283 $ (189) $ 94 Natural Gas and NGL Services 1,363 (904) 459 1,365 (805) 560 $ 1,646 $ (1,128) $ 518 $ 1,648 $ (994) $ 654 (1) Amortization expense attributable to the Crude Oil and Products Logistics segment for the years ended December 31, 2024 and 2023 was $35 million and $36 million, respectively. Amortization expense attributable to the Natural Gas and NGL Services segment for the years ended December 31, 2024 and 2023 was $99 million and $92 million, respectively.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Estimated future amortization expense related to the intangible assets at December 31, 2024 is as follows: (In millions) 2025 $ 121 2026 112 2027 84 2028 67 2029 16 2030 and thereafter 118 Total $ 518

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	The following table presents the impact on the Consolidated Balance Sheets of MPLX’s financial instruments carried at fair value on a recurring basis as of December 31, 2024 and 2023 by fair value hierarchy level. December 31, 2024 2023 (In millions) Asset Liability Asset Liability Embedded derivatives in commodity contracts (Level 3) Other current assets / Other current liabilities $ — $ 10 $ — $ 11 Other noncurrent assets / Other long-term liabilities — 48 — 50 Total carrying value in Consolidated Balance Sheets $ — $ 58 $ — $ 61
Schedule of changes in Level 3 fair value measurements [Table Text Block]	The following table is a reconciliation of the net beginning and ending balances recorded for net liabilities classified as Level 3 in the fair value hierarchy. (In millions) 2024 2023 Beginning balance $ (61) $ (61) Unrealized and realized (loss)/gain included in Net Income (1) (10) (11) Settlements 13 11 Ending balance (58) (61) The amount of total loss for the period included in earnings attributable to the change in unrealized gain relating to liabilities still held at end of period $ (7) $ (9) (1) (Loss)/gain on derivatives embedded in commodity contracts are recorded in Purchased product costs
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	The following table summarizes the fair value and carrying value of our third-party debt, excluding finance leases and unamortized debt issuance costs: December 31, 2024 2023 (In millions) Fair Value Carrying Value Fair Value Carrying Value Outstanding debt (1) $ 19,574 $ 21,068 $ 19,377 $ 20,547 (1) Any amounts outstanding under the MPC Loan Agreement are not included in the table above, as the carrying value approximates fair value. This balance is reflected in Current liabilities - related parties in the Consolidated Balance Sheets.

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments, Gain (Loss) [Table Text Block]	The impact of MPLX’s derivative contracts not designated as hedging instruments and the location of gains and losses recognized in the Consolidated Statements of Income is summarized below: (In millions) 2024 2023 2022 Product sales Realized gain $ 1 $ 7 $ — Product sales derivative gain 1 7 — Purchased product costs Realized loss (13) (11) (12) Unrealized gain 3 — 47 Purchased product cost derivative (loss)/gain (10) (11) 35 Total derivative (loss)/gain included in Net Income $ (9) $ (4) $ 35

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Schedule of Debt [Table Text Block]	MPLX’s outstanding borrowings consist of the following: December 31, (In millions) 2024 2023 MPLX LP: Bank revolving credit facility $ — $ — 4.875% senior notes due December 1, 2024 — 1,149 4.000% senior notes due February 15, 2025 500 500 4.875% senior notes due June 1, 2025 1,189 1,189 1.750% senior notes due March 1, 2026 1,500 1,500 4.125% senior notes due March 1, 2027 1,250 1,250 4.250% senior notes due December 1, 2027 732 732 4.000% senior notes due March 15, 2028 1,250 1,250 4.800% senior notes due February 15, 2029 750 750 2.650% senior notes due August 15, 2030 1,500 1,500 4.950% senior notes due September 1, 2032 1,000 1,000 5.000% senior notes due March 1, 2033 1,100 1,100 5.500% senior notes due June 1, 2034 1,650 — 4.500% senior notes due April 15, 2038 1,750 1,750 5.200% senior notes due March 1, 2047 1,000 1,000 5.200% senior notes due December 1, 2047 487 487 4.700% senior notes due April 15, 2048 1,500 1,500 5.500% senior notes due February 15, 2049 1,500 1,500 4.950% senior notes due March 14, 2052 1,500 1,500 5.650% senior notes due March 1, 2053 500 500 4.900% senior notes due April 15, 2058 500 500 Consolidated subsidiaries: MarkWest - 4.875% senior notes, due 2024-2025 11 12 ANDX - 4.250% - 5.200% senior notes, due 2027-2047 31 31 Financing lease obligations (1) 6 6 Total 21,206 20,706 Unamortized debt issuance costs (126) (122) Unamortized discount (132) (153) Amounts due within one year (1,693) (1,135) Total long-term debt due after one year $ 19,255 $ 19,296 (1) See Note 21 for lease information.
Schedule of Maturities of Long-Term Debt [Table Text Block]	The following table shows five years of scheduled debt payments, including payments on finance lease obligations, as of December 31, 2024: (In millions) 2025 $ 1,701 2026 1,501 2027 2,001 2028 1,250 2029 $ 750
Schedule of interest payable dates [Table Text Block]	Interest on each series of MPLX LP, MarkWest and ANDX senior notes outstanding is payable semi-annually in arrears, according to the table below. Senior Notes Interest payable semi-annually in arrears 4.000% senior notes due February 15, 2025 February 15 th and August 15 th 4.875% senior notes due June 1, 2025 June 1 st and December 1 st 1.750% senior notes due March 1, 2026 March 1 st and September 1 st 4.125% senior notes due March 1, 2027 March 1 st and September 1 st 4.250% senior notes due December 1, 2027 June 1 st and December 1 st 4.000% senior notes due March 15, 2028 March 15 th and September 15 th 4.800% senior notes due February 15, 2029 February 15 th and August 15 th 2.650% senior notes due August 15, 2030 February 15 th and August 15 th 4.950% senior notes due September 1, 2032 March 1 st and September 1 st 5.000% senior notes due March 1, 2033 March 1 st and September 1 st 5.500% senior notes due June 1, 2034 June 1 st and December 1 st 4.500% senior notes due April 15, 2038 April 15 th and October 15 th 5.200% senior notes due March 1, 2047 March 1 st and September 1 st 5.200% senior notes due December 1, 2047 June 1 st and December 1 st 4.700% senior notes due April 15, 2048 April 15 th and October 15 th 5.500% senior notes due February 15, 2049 February 15 th and August 15 th 4.950% senior notes due March 14, 2052 March 14 th and September 14 th 5.650% senior notes due March 1, 2053 March 1 st and September 1 st 4.900% senior notes due April 15, 2058 April 15 th and October 15 th

Net Interest and Other Financ_2

Net Interest and Other Financial Costs (Tables)	12 Months Ended
	Dec. 31, 2024
Other Income and Expenses [Abstract]
Interest and Other Income	Net interest and other financial costs were as follows: (In millions) 2024 2023 2022 Interest expense $ 963 $ 912 $ 852 Other financial costs 72 69 81 Interest income (95) (43) (4) Capitalized interest (19) (15) (9) Related-party interest and other financial costs — — 5 Net interest and other financial costs $ 921 $ 923 $ 925

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	The following tables represent a disaggregation of revenue for each reportable segment for the years ended December 31, 2024, 2023 and 2022: 2024 (In millions) Crude Oil and Products Logistics Natural Gas and NGL Services Total Revenues and other income: Service revenue $ 391 $ 2,379 $ 2,770 Service revenue - related parties 4,152 28 4,180 Service revenue - product related — 357 357 Product sales 5 1,652 1,657 Product sales - related parties 13 212 225 Total revenues from contracts with customers $ 4,561 $ 4,628 9,189 Non-ASC 606 revenue (1) 2,744 Total revenues and other income $ 11,933 2023 (In millions) Crude Oil and Products Logistics Natural Gas and NGL Services Total Revenues and other income: Service revenue $ 369 $ 2,170 $ 2,539 Service revenue - related parties 3,966 19 3,985 Service revenue - product related — 294 294 Product sales 5 1,660 1,665 Product sales - related parties 13 237 250 Total revenues from contracts with customers $ 4,353 $ 4,380 8,733 Non-ASC 606 revenue (1) 2,548 Total revenues and other income $ 11,281 2022 (In millions) Crude Oil and Products Logistics Natural Gas and NGL Services Total Revenues and other income: Service revenue $ 320 $ 2,039 $ 2,359 Service revenue - related parties 3,737 17 3,754 Service revenue - product related — 394 394 Product sales 6 2,213 2,219 Product sales - related parties 13 185 198 Total revenues from contracts with customers $ 4,076 $ 4,848 8,924 Non-ASC 606 revenue (1) 2,689 Total revenues and other income $ 11,613
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]	The tables below reflect the changes in ASC 606 contract balances for the years ended December 31, 2024 and 2023: (In millions) Balance at Additions/ (Deletions) Revenue Recognized (1) Balance at Contract assets $ 3 $ — $ (1) $ 2 Long-term contract assets 1 (1) — — Deferred revenue 59 86 (61) 84 Deferred revenue - related parties 47 90 (66) 71 Long-term deferred revenue 344 (29) — 315 Long-term deferred revenue - related parties $ 29 $ 15 $ — $ 44 (In millions) Balance at Additions/ (Deletions) Revenue Recognized (1) Balance at Contract assets $ 21 $ (18) $ — $ 3 Long-term contract assets 1 — — 1 Deferred revenue 57 42 (40) 59 Deferred revenue - related parties 63 86 (102) 47 Long-term deferred revenue 216 128 — 344 Long-term deferred revenue - related parties 25 4 — 29 Long-term contract liabilities $ 2 $ (2) $ — $ —
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	The table below includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially unsatisfied) as of December 31, 2024. The amounts presented below are generally limited to fixed consideration from contracts with customers that contain minimum volume commitments. A significant portion of our future contracted revenue is excluded from the amounts presented below in accordance with ASC 606. Variable consideration that is constrained or not required to be estimated as it reflects our efforts to perform is excluded from this disclosure. Additionally, we do not disclose information on the future performance obligations for any contract with an original expected duration of one year or less, or that are terminable by our customer with little or no termination penalties. Potential future performance obligations related to renewals that have not yet been exercised or are not certain of exercise are excluded from the amounts presented below. Revenues classified as Rental income and Sales-type lease revenue are also excluded from this table as they are disclosed in Note 21. (In billions) 2025 $ 2.2 2026 2.0 2027 1.8 2028 0.6 2029 0.3 2030 and thereafter 0.5 Total revenue on remaining performance obligations $ 7.4 As of December 31, 2024, unsatisfied performance obligations included in the Consolidated Balance Sheets are $514 million and will be recognized as revenue as the obligations are satisfied, which is generally expected to occur over the next 19 years. A portion of this amount is not disclosed in the table above as it is deemed variable consideration due to volume variability.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2024
Supplemental Cash Flow Information [Abstract]
Summary of Supplemental Cash Flow Information	(In millions) 2024 2023 2022 Net cash provided by operating activities included: Interest paid (net of amounts capitalized) $ 940 $ 893 $ 813 Income taxes paid 6 7 3 Cash paid for amounts included in the measurement of lease liabilities: Payments on operating leases 71 71 73 Net cash provided by financing activities included: Principal payments under finance lease obligations 1 1 2 Non-cash investing and financing activities: Net transfers of property, plant and equipment (to)/from materials and supplies inventories — (8) (1) ROU assets obtained in exchange for new operating lease obligations 47 21 78 ROU assets obtained in exchange for new finance lease obligations 1 — 1 Book value of equity method investment (1) 4 311 — (1) Represents the book value of MPLX’s equity method investment in OCC in 2024 and Torñado in 2023 prior to MPLX buying out the remaining interest in these entities. See Note 4 for additional information.
Summary of Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures [Table Text Block]	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) 2024 2023 2022 Additions to property, plant and equipment $ 1,056 $ 937 $ 806 (Decrease)/Increase in capital accruals (6) 82 47 Total capital expenditures $ 1,050 $ 1,019 $ 853

Leases Disclosure (Tables)

Leases Disclosure (Tables)	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Lease, Cost [Table Text Block]	The components of lease cost were as follows: 2024 2023 2022 (In millions) Related Party Third Related Third Related Third Components of lease costs: Operating lease costs $ 14 $ 58 $ 14 $ 56 $ 15 $ 61 Finance lease cost: Amortization of ROU assets — 1 — 1 — 1 Interest on lease liabilities — — — — — 1 Total finance lease cost — 1 — 1 — 2 Variable lease cost 4 12 4 10 2 16 Short-term lease cost 1 71 1 61 — 45 Total lease cost $ 19 $ 142 $ 19 $ 128 $ 17 $ 124
Supplemental Balance Sheet Disclosures [Text Block]	Supplemental balance sheet data related to leases were as follows: December 31, 2024 December 31, 2023 (In millions, except % and years) Related Party Third Party Related Party Third Party Operating leases Assets Right of use assets $ 226 $ 273 $ 227 $ 264 Liabilities Operating lease liabilities 2 45 1 45 Long-term operating lease liabilities 224 217 226 211 Total operating lease liabilities $ 226 $ 262 $ 227 $ 256 Weighted average remaining lease term 42 years 8 years 43 years 9 years Weighted average discount rate 5.8 % 4.2 % 5.8 % 4.2 % Finance leases Assets Property, plant and equipment, gross $ 10 $ 10 Less: Accumulated depreciation 5 5 Property, plant and equipment, net 5 5 Liabilities Long-term debt due within one year 1 1 Long-term debt 5 5 Total finance lease liabilities $ 6 $ 6 Weighted average remaining lease term 22 years 20 years Weighted average discount rate 6.0 % 6.0 %
Lessee, Operating Lease, Liability, to be Paid, Maturity	As of December 31, 2024, maturities of lease liabilities for operating lease obligations and finance lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows: (In millions) Related Party Operating Third Party Operating Finance 2025 $ 15 $ 55 $ 2 2026 15 48 2 2027 14 40 1 2028 14 37 — 2029 14 30 — 2030 and thereafter 532 97 7 Gross lease payments 604 307 12 Less: Imputed interest 378 45 6 Total lease liabilities $ 226 $ 262 $ 6
Finance Lease, Liability, to be Paid, Maturity	As of December 31, 2024, maturities of lease liabilities for operating lease obligations and finance lease obligations having initial or remaining non-cancellable lease terms in excess of one year are as follows: (In millions) Related Party Operating Third Party Operating Finance 2025 $ 15 $ 55 $ 2 2026 15 48 2 2027 14 40 1 2028 14 37 — 2029 14 30 — 2030 and thereafter 532 97 7 Gross lease payments 604 307 12 Less: Imputed interest 378 45 6 Total lease liabilities $ 226 $ 262 $ 6
Operating Lease, Lease Income [Table Text Block]	Lease revenues included on the Consolidated Statements of Income during 2024, 2023 and 2022 were as follows: 2024 2023 2022 (In millions) Related Party Third Related Party Third Related Party Third Operating leases: Rental income $ 853 $ 251 $ 822 $ 243 $ 763 $ 327 Sales-type leases: Interest income (Sales-type rental revenue - fixed minimum) 455 114 467 114 447 46 Interest income (Revenue from variable lease payments) 20 22 33 22 18 16 Sales-type lease revenue $ 475 $ 136 $ 500 $ 136 $ 465 $ 62
Sales-type Lease, Lease Income [Table Text Block]	Lease revenues included on the Consolidated Statements of Income during 2024, 2023 and 2022 were as follows: 2024 2023 2022 (In millions) Related Party Third Related Party Third Related Party Third Operating leases: Rental income $ 853 $ 251 $ 822 $ 243 $ 763 $ 327 Sales-type leases: Interest income (Sales-type rental revenue - fixed minimum) 455 114 467 114 447 46 Interest income (Revenue from variable lease payments) 20 22 33 22 18 16 Sales-type lease revenue $ 475 $ 136 $ 500 $ 136 $ 465 $ 62
Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity [Table Text Block]	The following is a schedule of minimum future rental payments to be received on the non-cancellable operating leases as of December 31, 2024: (In millions) Related Party Third Party Total 2025 $ 759 $ 98 $ 857 2026 734 77 811 2027 618 55 673 2028 332 47 379 2029 182 46 228 2030 and thereafter 235 214 449 Total minimum future rentals $ 2,860 $ 537 $ 3,397
Sales-type and Direct Financing Leases, Lease Receivable, Maturity [Table Text Block]	Annual minimum undiscounted lease payment receipts under our sales-type leases were as follows as of December 31, 2024: (In millions) Related Party Third Party Total 2025 $ 496 $ 172 $ 668 2026 479 157 636 2027 381 147 528 2028 107 138 245 2029 56 130 186 2030 and thereafter 119 896 1,015 Total minimum future rentals 1,638 1,640 3,278 Less: Imputed interest 757 707 1,464 Lease receivable (1) $ 881 $ 933 $ 1,814 Current lease receivables (2) $ 204 $ 102 $ 306 Long-term lease receivables (3) 677 831 1,508 Unguaranteed residual assets (3) 189 95 284 Total sales-type lease assets $ 1,070 $ 1,028 $ 2,098 (1) This amount does not include the unguaranteed residual assets. (2) The related-party balance is presented in Current assets - related parties and the third-party balance is presented in Receivables, net in the Consolidated Balance Sheets. (3) The related-party balance is presented in Noncurrent assets - related parties and the third-party balance is presented in Other noncurrent assets in the Consolidated Balance Sheets.
Schedule of Property Subject to or Available for Operating Lease [Table Text Block]	The following schedule summarizes MPLX’s investment in assets held under operating lease by major classes as of December 31, 2024 and 2023: December 31, (In millions) 2024 2023 Pipelines $ 689 $ 677 Refining logistics 1,430 1,399 Terminals 1,310 1,267 Marine 126 126 Gathering and transportation 86 86 Processing and fractionation 1,039 1,000 Land, building and other 171 165 Total property, plant and equipment 4,851 4,720 Less: accumulated depreciation 2,378 2,124 Property, plant and equipment, net $ 2,473 $ 2,596

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Contractual Obligation, Fiscal Year Maturity Schedule	MPLX executed various third-party transportation, terminalling, and gathering and processing agreements that obligate us to minimum volume, throughput or payment commitments over the remaining terms, which range from less than one year to seven years. After the minimum volume commitments are met in these agreements, MPLX pays additional amounts based on throughput. These agreements may include escalation clauses based on various inflationary indices; however, those potential increases have not been incorporated in minimum fees due under these agreements presented below. The minimum future payments under these agreements as of December 31, 2024 are as follows: (In millions) 2025 $ 166 2026 152 2027 136 2028 125 2029 87 2030 and thereafter 9 Total $ 675

Description of Business and B_3

Description of Business and Basis of Presentation (Details)			12 Months Ended
	Oct. 31, 2012	Mar. 27, 2012	Dec. 31, 2024
Limited Liability Company or Limited Partnership, Business Organization and Operations [Abstract]
Date of partnership formation		Mar. 27, 2012
Date for initial public offering completed	Oct. 31, 2012
Number of reportable segments			2

Summary of Principal Accounti_3

Summary of Principal Accounting Policies (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Asset Retirement Obligation	$ 41	$ 39

Acquisitions (Details)

Acquisitions (Details) - USD ($) $ in Millions					12 Months Ended
	Jul. 31, 2024	May 29, 2024	Mar. 22, 2024	Dec. 15, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	May 28, 2024
Business Acquisition [Line Items]
Payments to Acquire Interest in Joint Venture					$ 464	$ 98	$ 217
Investments - redemptions, repayments, return of capital and sales proceeds					146	3	11
Contract with Customer, Asset, Noncurrent					0	1	$ 1
Equity method investments					$ 4,531	$ 3,743
Utica Midstream
Business Acquisition [Line Items]
Business Acquisition, Description of Acquired Entity			On March 22, 2024, MPLX used $625 million of cash on hand to purchase additional ownership interest in existing joint ventures and gathering assets (the “Utica Midstream Acquisition”), which will enhance our position in the Utica basin. Prior to the acquisition, we owned an indirect interest in Ohio Gathering Company L.L.C. (“OGC”) and a direct interest in Ohio Condensate Company L.L.C. (“OCC”) and now own a combined 73 percent interest in OGC, a 100 percent interest in OCC, and a 100 percent interest in a dry gas gathering system in the Utica basin, including 53 miles of gathering pipeline and three dehydration units with a combined capacity of approximately 620 MMcf/d.
Payments to Acquire Businesses, Gross			$ 625
Business Acquisition, Percentage of Voting Interests Acquired			100%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets			$ 507
Recognized Identifiable Assets Acquired and Liabilities Assumed, Net			$ 625
Ohio Gathering Company L.L.C.
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage			73%
Basis difference			$ 75
Ohio Condensate Company, L.L.C.
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage			100%
Equity Interest in Acquiree, Percentage			62%
Equity Interest in Acquiree, Remeasurement Gain			$ 20
MarkWest Tornado GP, L.L.C.
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross				$ 270
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage				100%
Equity Interest in Acquiree, Percentage				60%
Equity Interest in Acquiree, Remeasurement Gain				$ 92
Recognized Identifiable Assets Acquired and Liabilities Assumed, Net				$ 673
Equity Method Investment, Remaining Ownership Interest Purchased				40%
Payments to Acquire Additional Interest in Subsidiaries				$ 303
Contract with Customer, Asset, Noncurrent				33
Equity method investments				311
Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment				585
Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				75
Recognized Identifiable Assets Acquired and Liabilities Assumed, Working Capital, Net				30
Recognized Identifiable Other Long-term Assets Acquired and Liabilities Assumed, Net				$ (17)
BANGL, LLC
Business Acquisition [Line Items]
Equity Method Investment, Additional Ownership Acquired	20%
Payments to Acquire Interest in Joint Venture	$ 210
Ownership percentage	45%
Basis difference	$ 156
WPC Parent, LLC
Business Acquisition [Line Items]
Gain (Loss) on Disposition of Stock in Subsidiary or Equity Method Investee		$ 151
Investments - redemptions, repayments, return of capital and sales proceeds		$ 134
WPC Parent, LLC | Enbridge Inc.
Business Acquisition [Line Items]
Ownership percentage		19%
WPC Parent, LLC | MPLX LP [Member]
Business Acquisition [Line Items]
Ownership percentage		30.40%
Whistler Pipeline LLC [Member] | MPLX LP [Member]
Business Acquisition [Line Items]
Ownership percentage								37.50%

Investments and Noncontrollin_3

Investments and Noncontrolling Interest (Equity Method Investments) (Details) - USD ($) $ in Millions		Dec. 31, 2024	Jul. 31, 2024	Mar. 22, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 4,531			$ 3,743
BANGL, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage			45%
Equity Method Investment, Additional Ownership Acquired			20%
Crude Oil and Products Logistics [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 1,595			1,517
Crude Oil and Products Logistics [Member] | Illinois Extension Pipeline Company, L.L.C.
Schedule of Equity Method Investments [Line Items]
Ownership percentage		35%
Equity method investments		$ 218			228
Crude Oil and Products Logistics [Member] | LOOP LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage		41%
Equity method investments		$ 310			314
Crude Oil and Products Logistics [Member] | MarEn Bakken Company LLC(1)
Schedule of Equity Method Investments [Line Items]
Ownership percentage		25%
Equity method investments	[1]	$ 526			449
Crude Oil and Products Logistics [Member] | Other VIEs and Non-VIEs [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	[2]	$ 541			526
Crude Oil and Products Logistics [Member] | Bakken Pipeline System | Indirect Ownership Interest
Schedule of Equity Method Investments [Line Items]
Ownership percentage		9.19%
Natural Gas & NGL Services [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 2,936			2,226
Natural Gas & NGL Services [Member] | Other VIEs and Non-VIEs [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	[2]	$ 418			437
Natural Gas & NGL Services [Member] | BANGL, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage	[3]	45%
Equity method investments		$ 281			63
Natural Gas & NGL Services [Member] | MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C.
Schedule of Equity Method Investments [Line Items]
Ownership percentage		67%
Equity method investments		$ 329			336
Natural Gas & NGL Services [Member] | MarkWest Utica EMG, L.L.C.
Schedule of Equity Method Investments [Line Items]
Ownership percentage		59%
Equity method investments		$ 742			676
Natural Gas & NGL Services [Member] | Ohio Gathering Company L.L.C.
Schedule of Equity Method Investments [Line Items]
Ownership percentage		35%		36%
Equity method investments	[4]	$ 470			0
Natural Gas & NGL Services [Member] | Ohio Gathering Company L.L.C. | Indirect Ownership Interest
Schedule of Equity Method Investments [Line Items]
Ownership percentage		38%
Natural Gas & NGL Services [Member] | Sherwood Midstream LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage		50%
Equity method investments		$ 488			500
Natural Gas & NGL Services [Member] | WPC Parent, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage	[5]	30%
Equity method investments	[5]	$ 208			$ 214
[1]The investment in MarEn Bakken Company LLC includes our 9.19 percent indirect interest in a joint venture (“Dakota Access”) that owns and operates the Dakota Access Pipeline and Energy Transfer Crude Oil Pipeline projects (collectively referred to as the “Bakken Pipeline system”).[2]Some investments included within Other have also been deemed to be VIEs.[3] In July 2024, we purchased an additional 20 percent ownership interest in BANGL, LLC, increasing our ownership interest to 45 percent, as discussed in Note 4.

Investments and Noncontrollin_4

Investments and Noncontrolling Interests (Summary of Equity Method Investment Financial Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Revenues and other income	$ 11,933	$ 11,281	$ 11,613
Costs and expenses	6,645	6,381	6,702
Net income	4,357	3,966	3,978
Assets, Current	3,276	2,808
Liabilities, Current	3,235	2,624
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Revenues and other income	3,594	3,262	2,653
Costs and expenses	1,535	1,331	1,251
Income from operations	2,059	1,930	1,402
Net income	1,631	1,634	$ 1,246
Assets, Current	1,570	1,531
Assets, Noncurrent	17,927	13,860
Liabilities, Current	746	979
Liabilities, Noncurrent	$ 6,711	$ 4,856

Investments and Noncontrollin_5

Investments and Noncontrolling Interests (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Natural Gas & NGL Services [Member]
Schedule of Equity Method Investments [Line Items]
Basis difference	$ 198	$ (30)
Basis difference, not amortized	31	31
Crude Oil and Products Logistics [Member]
Schedule of Equity Method Investments [Line Items]
Basis difference	291	299
Basis difference, not amortized	$ 167	$ 167

Related Party Agreements and _3

Related Party Agreements and Transactions (Narrative) (Detail) - Related Party	12 Months Ended
	Dec. 31, 2024
Fuels Distribution [Member]
Related Party Transaction [Line Items]
Term Of Agreements	10 years
Renewal Term Agreement	5 years
Marine Services Equipment [Member]
Related Party Transaction [Line Items]
Renewal Term Agreement	5 years
Number of renewals	1
Co-location Agreements [Member]
Related Party Transaction [Line Items]
Term Of Agreements	50 years
Marine Management Services [Member]
Related Party Transaction [Line Items]
Term Of Agreements	5 years
Renewal Term Agreement	5 years
Minimum | Marine Services Equipment [Member]
Related Party Transaction [Line Items]
Term Of Agreements	5 years
Maximum | Marine Services Equipment [Member]
Related Party Transaction [Line Items]
Term Of Agreements	6 years
Operating Agreements [Member] | Minimum
Related Party Transaction [Line Items]
Term Of Agreements	1 year
Operating Agreements [Member] | Maximum
Related Party Transaction [Line Items]
Term Of Agreements	10 years

Related Party Agreements and _4

Related Party Agreements and Transactions (Intercompany Loans with Related Parties) (Detail) - Revolving Credit Facility - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Repayments of Related Party Debt	$ 0	$ 0	$ 4,439
Proceeds from Related Party Debt	0	0	$ 2,989
Related Party
Related Party Transaction [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 1,500
Debt Instrument, Description of Variable Rate Basis	one-month term SOFR adjusted upward by 0.10 percent plus 1.25 percent
Interest rate during period			1.50%
Line of Credit, Current	$ 0	$ 0	$ 0

Related Party Agreements and _5

Related Party Agreements and Transactions (Summary of Revenue by Income Statement RP Line Item) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party
Related Party Transaction [Line Items]
Sales Revenue, Goods, Related Party, Net Zero	$ 754	$ 739	$ 1,002

Related Party Agreements and _6

Related Party Agreements and Transactions (Summary of Expenses by Income Statement RP Line Item) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
General and administrative expenses	$ 427	$ 379	$ 335
Marathon Petroleum Corporation [Member]
Related Party Transaction [Line Items]
General and administrative expenses	289	262	235
Construction-in-progress | Marathon Petroleum Corporation [Member]
Related Party Transaction [Line Items]
Property, Plant and Equipment, Additions	$ 182	$ 94	$ 70

Related Party Agreements and _7

Related Party Agreements and Transactions (Summary of Balance Sheet by RP Line Item) (Details) - USD ($) $ in Millions		Dec. 31, 2024		Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Receivables, net		$ 718		$ 823
Lease receivables	[1]	306
Other current assets		29		30
Long-term lease receivables	[2]	1,508
Long-term lease receivables		273		264
Unguaranteed residual asset	[2]	284
Deferred Revenue, Noncurrent		317		347
Related Party
Related Party Transaction [Line Items]
Receivables, net		620		587
Lease receivables		204	[1]	149
Prepaid		5		5
Other current assets		1		7
Other Receivables, Net, Current		830		748
Long-term lease receivables		677	[2]	789
Long-term lease receivables		226		227
Unguaranteed residual asset		189	[2]	126
Long-term receivables		28		19
Other Receivable, after Allowance for Credit Loss, Noncurrent		1,120		1,161
MPC loan agreement and other payables(1)	[3]	288		278
Deferred revenue		106		81
Operating lease liabilities		2		1
Other Liabilities, Current		396		360
Long-term operating lease liabilities		224		226
Deferred Revenue, Noncurrent		110		99
Other Liabilities, Noncurrent		334		325
Related Party | Revolving Credit Facility
Related Party Transaction [Line Items]
Line of Credit, Current		$ 0		$ 0	$ 0
[1]The related-party balance is presented in Current assets - related parties and the third-party balance is presented in Receivables, net in the Consolidated Balance Sheets.[2]The related-party balance is presented in Noncurrent assets - related parties and the third-party balance is presented in Other noncurrent assets in the Consolidated Balance Sheets.[3] There were no borrowings outstanding on the MPC Loan Agreement as of December 31, 2024 or December 31, 2023.

Equity (Changes in Partners Cap

Equity (Changes in Partners Capital, Unit Rollforward) (Details) - shares		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Stockholders Equity [Line Items]
Units outstanding		1,017,142,290	1,003,498,875	1,001,020,616	1,016,178,378
Unit-based compensation awards		141,985	196,428	190,529
Conversion of Series A preferred units(1)	[1]	21,078,998	2,281,831
Units redeemed in unit repurchase program		(7,577,568)	0	(15,348,291)
Related Party
Stockholders Equity [Line Items]
Units outstanding		647,415,452
[1]Certain Series A preferred unitholders have exercised their rights to convert their Series A preferred units into common units as discussed in Note 9.

Repurchase Program (Details)

Repurchase Program (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Aug. 02, 2022	Nov. 02, 2020
Equity, Class of Treasury Stock [Line Items]
Authorized Amount					$ 1,000	$ 1,000
Number of units repurchased		7,577,568	0	15,348,291
Cash Paid for Units Repurchased	[1]	$ 326	$ 0	$ 491
Average cost per unit(1)	[1]	$ 43.04	$ 0	$ 31.96
Remaining Authorized Repurchase Amount		$ 520
[1] Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.

Equity (Cash Distributions) (De

Equity (Cash Distributions) (Details) - USD ($) $ / shares in Units, $ in Millions					12 Months Ended
	Feb. 14, 2025	Feb. 03, 2025	Jan. 22, 2025	Feb. 15, 2023	Dec. 31, 2024	Dec. 31, 2023		Dec. 31, 2022
Distribution Made to Limited Partner [Line Items]
Cash Distributions Declared					$ 3,705	$ 3,355		$ 3,109
Distributions Declared, Per Unit					$ 3.613	$ 3.250		$ 2.960
Common Unit-holders Public
Distribution Made to Limited Partner [Line Items]
Cash Distributions Declared					$ 3,678	$ 3,256		$ 2,980
Series A Preferred Stock [Member]
Distribution Made to Limited Partner [Line Items]
Cash Distributions Declared					27	94		88
Series B Preferred Stock [Member]
Distribution Made to Limited Partner [Line Items]
Cash Distributions Declared					$ 0	$ 5	[1]	$ 41
Distribution date				Feb. 15, 2023
Subsequent Event
Distribution Made to Limited Partner [Line Items]
Distribution declaration date			Jan. 22, 2025
Cash Distributions Declared			$ 972
Distributions Declared, Per Unit			$ 0.9565
Subsequent Event | Common Unit-holders Public
Distribution Made to Limited Partner [Line Items]
Distribution date	Feb. 14, 2025
Distribution date of record		Feb. 03, 2025
[1]2023 period includes the portion of the $21 million distribution paid to the Series B preferred unitholders on February 15, 2023 that was earned during the period prior to the redemption.

Series B Preferred Units (Detai

Series B Preferred Units (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 15, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Partners' Capital Account, Distributions		$ 3,603	$ 3,243	$ 3,000
Series B Preferred Stock [Member]
Partners' Capital Account, Units, Redeemed	600,000
Preferred Stock, Dividend Rate, Percentage	6.875%
Preferred Stock, Redemption Price Per Share	$ 1,000
Preferred Stock, Redemption Terms	MPLX exercised its right to redeem all 600,000 units of 6.875 percent Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the “Series B preferred units”). MPLX paid unitholders the Series B preferred unit redemption price of $1,000 per unit.
Partners' Capital Account, Distributions	$ 21
Distribution date	Feb. 15, 2023

Net Income Per Limited Partne_2

Net Income Per Limited Partner Unit (Basic and Diluted Earnings Per Unit) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Net income attributable to MPLX LP:
Net income attributable to MPLX LP(1):	[1]	$ 4,317	$ 3,928	$ 3,944
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic		7	16	24
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted		7	16	24
Impact of redemption of Series B preferred units		0	5	0
Net Income Available to Common Unitholders, Basic		4,281	3,808	3,791
Net Income Available to Common Unitholders, Diluted		$ 4,281	$ 3,808	$ 3,791
Weighted average units outstanding:
Basic (shares)		1,016	1,001	1,010
Diluted (shares)		1,017	1,002	1,010
Net income attributable to MPLX LP per limited partner unit:
Basic (in USD per unit)		$ 4.21	$ 3.80	$ 3.75
Diluted (in USD per unit)		$ 4.21	$ 3.80	$ 3.75
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		1	1	1
Series A Preferred Stock [Member]
Net income attributable to MPLX LP:
Distributions declared on preferred units		$ 27	$ 94	$ 88
Series B Preferred Stock [Member]
Net income attributable to MPLX LP:
Distributions declared on preferred units		0	5	41
Restricted Stock Units (RSUs)
Net income attributable to MPLX LP:
Distributions declared on preferred units		$ 2	$ 0	$ 0
[1]Allocation of net income attributable to MPLX LP assumes all earnings for the period have been distributed based on the distribution priorities applicable to the period.

Redeemable Preferred Units (Nar

Redeemable Preferred Units (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions				12 Months Ended
		Jan. 22, 2025	May 13, 2016	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Redeemable Noncontrolling Interest [Line Items]
Distributions Declared, Per Unit				$ 3.613	$ 3.250	$ 2.960
Series A Preferred, Units, Converted	[1]			21,078,998	2,281,831
Series A Preferred Stock [Member]
Redeemable Noncontrolling Interest [Line Items]
Series A preferred, Units Issued			30,800,000
Preferred Stock, Dividend Rate, Percentage			6.50%
Units issued, price per unit			$ 32.50
Proceeds from issuance of preferred units			$ 984
Preferred units, dividend rate, per-dollar-amount			$ 0.528125
Series A preferred, Units Outstanding				6,000,000	27,000,000
Temporary Equity, Description				The holders may convert their Series A preferred units into common units at any time, in full or in part, subject to minimum conversion amounts and conditions. After the fourth anniversary of the issuance date, MPLX may convert the Series A preferred units into common units at any time, in whole or in part, subject to certain minimum conversion amounts and conditions, if the closing price of MPLX common units is greater than $48.75 for the 20-day trading period immediately preceding the conversion notice date. The conversion rate for the Series A preferred units shall be the quotient of (a) the sum of (i) $32.50, plus (ii) any unpaid cash distributions on the applicable preferred unit, divided by (b) $32.50, subject to adjustment for unit distributions, unit splits and similar transactions. The holders of the Series A preferred units are entitled to vote on an as-converted basis with the common unitholders and have certain other class voting rights with respect to any amendment to the MPLX partnership agreement that would adversely affect any rights, preferences or privileges of the preferred units. In addition, upon certain events involving a change of control, the holders of preferred units may elect, among other potential elections, to convert their Series A preferred units to common units at the then applicable change of control conversion rate.
Common Unit-holders Public
Redeemable Noncontrolling Interest [Line Items]
Series A Preferred, Units, Converted				21,000,000	2,000,000
Subsequent Event
Redeemable Noncontrolling Interest [Line Items]
Distribution declaration date		Jan. 22, 2025
Distributions Declared, Per Unit		$ 0.9565
[1]Certain Series A preferred unitholders have exercised their rights to convert their Series A preferred units into common units as discussed in Note 9.

Segment Information (Details)

Segment Information (Details)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Number of reportable segments	2

Segment Information - Revenues

Segment Information - Revenues and Adjusted EBITDA (Details) - USD ($) $ in Millions				12 Months Ended
		Aug. 01, 2024	Jul. 31, 2024	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax				$ 9,189		$ 8,733		$ 8,924
Sales-type lease revenue				136		136		62
Income from equity method investments				802		600		476
Capital expenditures				1,050		1,019		853
Total segment revenues and other income				11,933		11,281		11,613
Investments - acquisitions and contributions				464		98		217
BANGL, LLC
Segment Reporting, Revenue Reconciling Item [Line Items]
Investments - acquisitions and contributions			$ 210
Wink to Webster Pipeline LLC [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Investments - acquisitions and contributions		$ 18
Nonrelated Party
Segment Reporting, Revenue Reconciling Item [Line Items]
Rental Income				251		243		327
Sales-type lease revenue				136		136		62
Other Income				70		126		485
Sales-type Lease, Selling Profit (Loss)	[1]					509
Other Income [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Sales-type Lease, Selling Profit (Loss)						509
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Adjusted EBITDA				6,764		6,269		5,775
Segment Reconciling Items
Segment Reporting, Revenue Reconciling Item [Line Items]
Income from equity method investments				802		600		476
Crude Oil and Products Logistics [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax				4,561		4,353		4,076
Crude Oil and Products Logistics [Member] | Nonrelated Party
Segment Reporting, Revenue Reconciling Item [Line Items]
Total segment revenues and other income				746		701		574
Crude Oil and Products Logistics [Member] | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Rental Income				882		857		803
Sales-type lease revenue				475		500		465
Income from equity method investments				269		270		197
Other Income				152		68		57
Adjusted EBITDA	[2]			4,375		4,134		3,761
Capital expenditures				482		414		325
Investments - acquisitions and contributions				(93)	[3]	(8)		(63)	[3]
Total segment revenues and other income	[4]			6,339		6,048		5,598
Operating Expenses				2,097		2,006		1,937
Segment Reporting, Other Segment Item, Amount	[5]			(133)		(92)		(100)
Crude Oil and Products Logistics [Member] | Operating Segments | Pro rata share of JV debt repayment
Segment Reporting, Revenue Reconciling Item [Line Items]
Investments - acquisitions and contributions				(92)				(60)
Natural Gas & NGL Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax				4,628		4,380		4,848
Natural Gas & NGL Services [Member] | Nonrelated Party
Segment Reporting, Revenue Reconciling Item [Line Items]
Total segment revenues and other income				5,297		4,902		5,748
Natural Gas & NGL Services [Member] | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Rental Income				222		208		287
Sales-type lease revenue				136		136		62
Income from equity method investments				533	[6]	330		279
Other Income				75		179	[7]	539	[7]
Adjusted EBITDA	[2]			2,389		2,135		2,014
Capital expenditures				568		605		528
Investments - acquisitions and contributions				(143)	[3]	(90)		(154)
Total segment revenues and other income	[4]			5,594		5,233		6,015
Operating Expenses				1,704		1,564		1,472
Segment Reporting, Other Segment Item, Amount	[5]			(60)		(64)		466
Purchased product costs				1,561		1,598		2,063
Service [Member] | Crude Oil and Products Logistics [Member] | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax				4,543		4,335		4,057
Service [Member] | Natural Gas & NGL Services [Member] | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax				2,407		2,189		2,056
Product [Member] | Crude Oil and Products Logistics [Member] | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax				18		18		19
Product [Member] | Natural Gas & NGL Services [Member] | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax				$ 2,221		$ 2,191		$ 2,792
[1]The amount recognized on commencement date was recorded as a gain in Other income in the Consolidated Statements of Income.[2]See below for the reconciliation from Segment Adjusted EBITDA to Net income.[3]Investments in unconsolidated affiliates for the Crude Oil and Products Logistics segment include contributions of $92 million and $60 million for the years ended December 31, 2024 and 2022, respectively, to Dakota Access to fund our share of debt repayments by the joint venture and exclude $18 million related to the acquisition of additional interest in Wink to Webster Pipeline LLC for the year ended December 31, 2024. Investments in unconsolidated affiliates for the Natural Gas and NGL Services segment exclude $210 million related to the acquisition of additional interests in BANGL, LLC for the year ended December 31, 2024.[4]Within the total segment revenues and other income amounts presented above, third party revenues for the Crude Oil and Products Logistics segment were $746 million, $701 million and $574 million for the years ended December 31, 2024, 2023 and 2022, respectively. Third party revenues for the Natural Gas and NGL Services segment were $5,297 million, $4,902 million and $5,748 million for the years ended December 31, 2024, 2023 and 2022, respectively.[5]Other segment items in the Crude Oil and Products Logistics segment include income from equity method investments, distributions and adjustments related to equity method investments, equity-based compensation and other miscellaneous items. Other segment items in the Natural Gas and NGL Services segment include income from equity method investments, distributions and adjustments related to equity method investments, gains on sales-type leases and equity method investments, unrealized derivative gain/loss and other miscellaneous items.[6]Includes a $151 million gain related to the dilution of ownership interest in connection with the Whistler Joint Venture Transaction in 2024.[7]Includes a $92 million gain on remeasurement of our existing equity investment in Torñado in conjunction with the purchase of the remaining joint venture interest in 2023. Includes a $509 million gain on a lease reclassification for the year ended December 31, 2022. See Note 21 in the Consolidated Financial Statements for additional information.

Segment Information - Reconcili

Segment Information - Reconciliation Adjusted EBITDA to Net income (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022
Segment Reporting Information [Line Items]
Depreciation and amortization		$ 1,283		$ 1,213		$ 1,230
Income from equity method investments		802		600		476
Gain on sales-type leases and equity method investment		20		92		509
Net income		4,357		3,966		3,978
Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBITDA		6,764		6,269		5,775
Operating Segments | Crude Oil and Products Logistics [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	[1]	4,375		4,134		3,761
Depreciation and amortization		526		530		515
Income from equity method investments		269		270		197
Operating Segments | Natural Gas & NGL Services [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	[1]	2,389		2,135		2,014
Depreciation and amortization		757		683		715
Income from equity method investments		533	[2]	330		279
Segment Reconciling Items
Segment Reporting Information [Line Items]
Depreciation and amortization	[3]	1,283		1,213		1,230
Interest and Other Financial Costs		921		923		925
Income from equity method investments		802		600		476
Distributions/adjustments related to equity method investments		928		774		652
Gain on sales-type leases and equity method investment		0		92		509
Adjusted EBITDA attributable to noncontrolling interests		44		42		38
Garyville incident response costs		0		(16)	[4]	0
Other	[5]	$ (121)		$ (111)		$ (13)
[1]See below for the reconciliation from Segment Adjusted EBITDA to Net income.[2]Includes a $151 million gain related to the dilution of ownership interest in connection with the Whistler Joint Venture Transaction in 2024.[3]Depreciation and amortization attributable to Crude Oil and Products Logistics was $526 million, $530 million and $515 million for the years ended December 31, 2024, 2023 and 2022, respectively. Depreciation and amortization attributable to Natural Gas and NGL Services was $757 million, $683 million and $715 million for the years ended December 31, 2024, 2023 and 2022, respectively.[4]In August 2023, a naphtha release and resulting fire occurred at our Garyville Tank Farm resulting in the loss of four storage tanks with a combined shell capacity of 894 thousand barrels. We incurred $16 million of incident response costs, net of insurance recoveries, during the year ended December 31, 2023.[5]Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items

Major Customers and Concentra_2

Major Customers and Concentration of Credit Risk (Details) - Revenue Benchmark [Member] - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Nonrelated Party
Concentration Risk [Line Items]
Concentration risk, percentage		10%
Related Party
Concentration Risk [Line Items]
Concentration risk, percentage	49%	50%	47%
Crude Oil and Products Logistics [Member] | Related Party
Concentration Risk [Line Items]
Concentration risk, percentage	88%	88%	90%
Natural Gas & NGL Services [Member] | Related Party
Concentration Risk [Line Items]
Concentration risk, percentage	4%	5%	4%

Inventories (Summary of Invento

Inventories (Summary of Inventories) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
NGLs	$ 5	$ 8
Line fill	18	15
Spare parts, materials and supplies	157	136
Total inventories	$ 180	$ 159

Property, Plant and Equipment_2

Property, Plant and Equipment (Summary of Property, Plant and Equipment) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 28,404	$ 27,385
Less accumulated depreciation	9,250	8,121
Property, plant and equipment, net	19,154	19,264
Capitalized interest	19	15	$ 9
Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	13,189	12,779
Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	15,215	14,606
Pipelines And Related Assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6,627	6,455
Refining Logistics and related assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,867	1,818
Terminals and related assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,726	1,651
Marine [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,149	1,100
Land Building Office Equipment And Other [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,619	1,609
Land Building Office Equipment And Other [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	541	525
Gas Gathering And Transportation [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,789	7,484
Processing and fractionation [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6,611	6,203
Construction-in-progress | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	201	146
Construction-in-progress | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 274	$ 394
Minimum | Pipelines And Related Assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	15 years
Minimum | Refining Logistics and related assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	15 years
Minimum | Terminals and related assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	15 years
Minimum | Marine [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	15 years
Minimum | Land Building Office Equipment And Other [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Minimum | Land Building Office Equipment And Other [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Minimum | Gas Gathering And Transportation [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Minimum | Processing and fractionation [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	10 years
Maximum | Pipelines And Related Assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	50 years
Maximum | Refining Logistics and related assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Maximum | Terminals and related assets [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years
Maximum | Marine [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Maximum | Land Building Office Equipment And Other [Member] | Crude Oil and Products Logistics [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	60 years
Maximum | Land Building Office Equipment And Other [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years
Maximum | Gas Gathering And Transportation [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years
Maximum | Processing and fractionation [Member] | Natural Gas & NGL Services [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years

Goodwill and Intangibles (Goodw

Goodwill and Intangibles (Goodwill) (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Nov. 30, 2023	Dec. 31, 2022 USD ($)
Goodwill [Line Items]
Total Number of Reporting Units	5
Number of reporting units with goodwill	3
Goodwill	$ 7,645	$ 7,645		$ 7,645
Goodwill, Impairment Loss	$ 0
Crude Gathering [Member]
Goodwill [Line Items]
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount			10%
Measurement Input, Discount Rate [Member] | Goodwill | Income Approach Valuation Technique
Goodwill [Line Items]
Fair Value Inputs	8.50%

Goodwill and Intangibles (Recon

Goodwill and Intangibles (Reconciliation of Goodwill) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Gross goodwill	$ 10,786		$ 10,786
Goodwill, Impaired, Accumulated Impairment Loss	(3,141)		(3,141)
Goodwill	7,645	$ 7,645	7,645
Crude Oil and Products Logistics [Member]
Goodwill [Line Items]
Gross goodwill	7,645		7,645
Goodwill, Impaired, Accumulated Impairment Loss	0		0
Goodwill	7,645	7,645	7,645
Natural Gas & NGL Services [Member]
Goodwill [Line Items]
Gross goodwill	3,141		3,141
Goodwill, Impaired, Accumulated Impairment Loss	(3,141)		(3,141)
Goodwill	$ 0	$ 0	$ 0

Goodwill and Intangibles (Intan

Goodwill and Intangibles (Intangible Assets) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross Intangibles		$ 1,646	$ 1,648
Accumulated amortization	[1]	(1,128)	(994)
Intangibles, net		518	654
Crude Oil and Products Logistics [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangibles		283	283
Accumulated amortization	[1]	(224)	(189)
Intangibles, net		59	94
Amortization of Intangible Assets		35	36
Natural Gas & NGL Services [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangibles		1,363	1,365
Accumulated amortization	[1]	(904)	(805)
Intangibles, net		459	560
Amortization of Intangible Assets		$ 99	$ 92
[1]Amortization expense attributable to the Crude Oil and Products Logistics segment for the years ended December 31, 2024 and 2023 was $35 million and $36 million, respectively. Amortization expense attributable to the Natural Gas and NGL Services segment for the years ended December 31, 2024 and 2023 was $99 million and $92 million, respectively.

Goodwill and Intangibles (Futur

Goodwill and Intangibles (Future Amortization Expense) (Details) $ in Millions	Dec. 31, 2024 USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2025	$ 121
2026	112
2027	84
2028	67
2029	16
2030 and thereafter	118
Total future intangibles amortization expense	$ 518

Fair Value Measurements - Recur

Fair Value Measurements - Recurring (Financial Instruments by Valuation Hierarchy) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset	$ 0	$ 0
Derivative Liability, Subject to Master Netting Arrangement, before Offset	58	61
Fair Value, Inputs, Level 3 [Member] | Other current assets | Embedded Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset	0	0
Fair Value, Inputs, Level 3 [Member] | Other noncurrent assets | Embedded Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Subject to Master Netting Arrangement, before Offset	0	0
Fair Value, Inputs, Level 3 [Member] | Other current liabilities | Embedded Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset	10	11
Fair Value, Inputs, Level 3 [Member] | Other Noncurrent Liabilities [Member] | Embedded Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability, Subject to Master Netting Arrangement, before Offset	$ 48	$ 50

Fair Value Measurements - Rec_2

Fair Value Measurements - Recurring (Significant Unobservable Inputs in Level 3 Valuation) (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) $ / gal
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative, Average Forward Price | $ / gal	0.81
Embedded Derivative Financial Instruments [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Embedded Derivative Renewal Term	5 years
Embedded Derivative Financial Instruments [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs Probability of Renewal	100%
Minimum | Embedded Derivative Financial Instruments [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative, Forward Price	0.65
Maximum | Embedded Derivative Financial Instruments [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative, Forward Price	1.54

Fair Value Measurements - Rec_3

Fair Value Measurements - Recurring (Changes in Level 3 Measurements) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance		$ (61)	$ (61)
Unrealized and realized Gain (Loss) Included in Net Income	[1]	$ (10)	$ (11)
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Purchased product costs	Purchased product costs
Settlements		$ 13	$ 11
Ending balance		(58)	(61)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)		$ (7)	$ (9)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Purchased product costs	Purchased product costs
[1](Loss)/gain on derivatives embedded in commodity contracts are recorded in Purchased product costs

Fair Value Measurements - Repor

Fair Value Measurements - Reported (Details) - USD ($) $ in Millions		Dec. 31, 2024	Dec. 31, 2023
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	[1]	$ 21,068	$ 20,547
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	[1]	$ 19,574	$ 19,377
[1]Any amounts outstanding under the MPC Loan Agreement are not included in the table above, as the carrying value approximates fair value. This balance is reflected in Current liabilities - related parties in the Consolidated Balance Sheets.

Derivative Financial Instrume_3

Derivative Financial Instruments (Embedded Derivatives in Commodity Contracts) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Derivative [Line Items]
Description of Embedded Derivative	MPLX has a natural gas purchase commitment embedded in a keep-whole processing agreement with a producer customer in the Southern Appalachia region expiring in December 2027. The customer has the unilateral option to extend the agreement for one five-year term through December 2032. For accounting purposes, the natural gas purchase commitment and the term extending option have been aggregated into a single compound embedded derivative.
Embedded Derivative Financial Instruments [Member]
Derivative [Line Items]
Number of renewals	1
Derivative, Term of Contract	5 years
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Liability	$ 58	$ 61

Derivative Financial Instrume_4

Derivative Financial Instruments (Derivatives Income Statement Location) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net income	Net income	Net income
Derivative, Gain (Loss) on Derivative, Net	$ (9)	$ (4)	$ 35
Purchased product costs
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Realized Gain (Loss), Net	(13)	(11)	(12)
Unrealized Gain (Loss) on Derivatives and Commodity Contracts	$ 3	$ 0	$ 47
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of revenues (excludes items below)	Cost of revenues (excludes items below)	Cost of revenues (excludes items below)
Derivative, Gain (Loss) on Derivative, Net	$ (10)	$ (11)	$ 35
Product sales
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Realized Gain (Loss), Net	$ 1	$ 7	$ 0
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Revenue from Contract with Customer, Excluding Assessed Tax, Third parties	Revenue from Contract with Customer, Excluding Assessed Tax, Third parties	Revenue from Contract with Customer, Excluding Assessed Tax, Third parties
Derivative, Gain (Loss) on Derivative, Net	$ 1	$ 7	$ 0

Debt (Summary of Outstanding Bo

Debt (Summary of Outstanding Borrowings) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 01, 2024	May 20, 2024	Dec. 31, 2023	Mar. 13, 2023	Feb. 09, 2023
Debt Instrument [Line Items]
Finance Lease, Liability	[1]	$ 6			$ 6
Debt and capital lease obligations		21,206			20,706
Unamortized debt issuance costs		126			122
Unamortized discount		132			153
Debt, Current		1,693			1,135
Total long-term debt due after one year		19,255			19,296
MPLX Revolving Credit Facility due July 2027
Debt Instrument [Line Items]
Outstanding balance		0
MPLX Revolving Credit Facility due July 2024 [Member]
Debt Instrument [Line Items]
Outstanding balance					0
Senior Notes | Senior Notes Due July 2023 [Member]
Debt Instrument [Line Items]
Interest Rate						4.50%
Senior Notes | Senior Note Due March 2033
Debt Instrument [Line Items]
Interest Rate							5%
Debt Instrument, Face Amount							$ 1,100
Senior Notes | Senior Note Due June 2034
Debt Instrument [Line Items]
Interest Rate				5.50%
Debt Instrument, Face Amount				$ 1,650
Senior Notes | Senior Note Due March 2053
Debt Instrument [Line Items]
Interest Rate							5.65%
Debt Instrument, Face Amount							$ 500
MPLX LP | Senior Notes | Senior Notes Due December 2024 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 0			1,149
Interest Rate		4.875%	4.875%
Maturity Date		Dec. 01, 2024
MPLX LP | Senior Notes | Senior Notes Due February 2025 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 500			500
Interest Rate		4%
Maturity Date		Feb. 15, 2025
MPLX LP | Senior Notes | Senior Notes Due June 2025 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,189			1,189
Interest Rate		4.875%
Maturity Date		Jun. 01, 2025
MPLX LP | Senior Notes | Senior Notes Due March 2026 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,500			1,500
Interest Rate		1.75%
Maturity Date		Mar. 01, 2026
MPLX LP | Senior Notes | 4.125% senior notes due March 2027
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,250			1,250
Interest Rate		4.125%
Maturity Date		Mar. 01, 2027
MPLX LP | Senior Notes | Senior Notes Due December 2027 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 732			732
Interest Rate		4.25%
Maturity Date		Dec. 01, 2027
MPLX LP | Senior Notes | Senior Notes Due March 2028 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,250			1,250
Interest Rate		4%
Maturity Date		Mar. 15, 2028
MPLX LP | Senior Notes | Senior Notes Due February 2029 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 750			750
Interest Rate		4.80%
Maturity Date		Feb. 15, 2029
MPLX LP | Senior Notes | Senior Notes Due August 2030 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,500			1,500
Interest Rate		2.65%
Maturity Date		Aug. 15, 2030
MPLX LP | Senior Notes | Senior Note Due September 2032
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,000			1,000
Interest Rate		4.95%
Maturity Date		Sep. 01, 2032
MPLX LP | Senior Notes | Senior Note Due March 2033
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,100			1,100
Interest Rate		5%
Maturity Date		Mar. 01, 2033
MPLX LP | Senior Notes | Senior Note Due June 2034
Debt Instrument [Line Items]
Interest Rate		5.50%
Maturity Date		Jun. 01, 2034
MPLX LP | Senior Notes | Senior Notes Due April 2038 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,750			1,750
Interest Rate		4.50%
Maturity Date		Apr. 15, 2038
MPLX LP | Senior Notes | 5.200% senior notes due March 2047
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,000			1,000
Interest Rate		5.20%
Maturity Date		Mar. 01, 2047
MPLX LP | Senior Notes | Senior Notes Due December 2047 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 487			487
Interest Rate		5.20%
Maturity Date		Dec. 01, 2047
MPLX LP | Senior Notes | Senior Notes Due April 2048 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,500			1,500
Interest Rate		4.70%
Maturity Date		Apr. 15, 2048
MPLX LP | Senior Notes | Senior Notes Due February 2049 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,500			1,500
Interest Rate		5.50%
Maturity Date		Feb. 15, 2049
MPLX LP | Senior Notes | Senior Note Due March 2052 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,500			1,500
Interest Rate		4.95%
Maturity Date		Mar. 14, 2052
MPLX LP | Senior Notes | Senior Note Due March 2053
Debt Instrument [Line Items]
Long-term debt, gross		$ 500			500
Interest Rate		5.65%
Maturity Date		Mar. 01, 2053
MPLX LP | Senior Notes | Senior Notes Due April 2058 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 500			500
Interest Rate		4.90%
Maturity Date		Apr. 15, 2058
MarkWest | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 11			12
MarkWest | Senior Notes | Maximum
Debt Instrument [Line Items]
Interest Rate		4.875%
MarkWest | Senior Notes | Senior Notes Due December 2024 [Member]
Debt Instrument [Line Items]
Interest Rate			4.875%
ANDX LP [Member] | Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 31			$ 31
ANDX LP [Member] | Senior Notes | Minimum
Debt Instrument [Line Items]
Interest Rate		4.25%
ANDX LP [Member] | Senior Notes | Maximum
Debt Instrument [Line Items]
Interest Rate		5.20%
[1]See Note 21 for lease information.

Debt (Summary of Outstanding _2

Debt (Summary of Outstanding Borrowings Interest Rates and Table Due Dates) (Details) - Senior Notes	12 Months Ended
	Dec. 31, 2024	May 20, 2024	Feb. 09, 2023
Senior Note Due March 2033
Debt Instrument [Line Items]
Interest rate, stated percentage			5%
Senior Note Due June 2034
Debt Instrument [Line Items]
Interest rate, stated percentage		5.50%
Senior Note Due March 2053
Debt Instrument [Line Items]
Interest rate, stated percentage			5.65%
MPLX LP | Senior Notes Due February 2025 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4%
Debt Instrument, Maturity Date	Feb. 15, 2025
MPLX LP | Senior Notes Due June 2025 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4.875%
Debt Instrument, Maturity Date	Jun. 01, 2025
MPLX LP | Senior Notes Due March 2026 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	1.75%
Debt Instrument, Maturity Date	Mar. 01, 2026
MPLX LP | Senior Notes Due March 2027 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4.125%
Debt Instrument, Maturity Date	Mar. 01, 2027
MPLX LP | Senior Notes Due December 2027 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4.25%
Debt Instrument, Maturity Date	Dec. 01, 2027
MPLX LP | Senior Notes Due March 2028 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4%
Debt Instrument, Maturity Date	Mar. 15, 2028
MPLX LP | Senior Notes Due February 2029 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4.80%
Debt Instrument, Maturity Date	Feb. 15, 2029
MPLX LP | Senior Notes Due August 2030 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	2.65%
Debt Instrument, Maturity Date	Aug. 15, 2030
MPLX LP | Senior Note Due September 2032
Debt Instrument [Line Items]
Interest rate, stated percentage	4.95%
Debt Instrument, Maturity Date	Sep. 01, 2032
MPLX LP | Senior Note Due March 2033
Debt Instrument [Line Items]
Interest rate, stated percentage	5%
Debt Instrument, Maturity Date	Mar. 01, 2033
MPLX LP | Senior Note Due June 2034
Debt Instrument [Line Items]
Interest rate, stated percentage	5.50%
Debt Instrument, Maturity Date	Jun. 01, 2034
MPLX LP | Senior Notes Due April 2038 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4.50%
Debt Instrument, Maturity Date	Apr. 15, 2038
MPLX LP | 5.200% senior notes due March 2047
Debt Instrument [Line Items]
Interest rate, stated percentage	5.20%
Debt Instrument, Maturity Date	Mar. 01, 2047
MPLX LP | Senior Notes Due December 2047 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	5.20%
Debt Instrument, Maturity Date	Dec. 01, 2047
MPLX LP | Senior Notes Due April 2048 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4.70%
Debt Instrument, Maturity Date	Apr. 15, 2048
MPLX LP | Senior Notes Due November 2049 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	5.50%
Debt Instrument, Maturity Date	Feb. 15, 2049
MPLX LP | Senior Note Due March 2052 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4.95%
Debt Instrument, Maturity Date	Mar. 14, 2052
MPLX LP | Senior Note Due March 2053
Debt Instrument [Line Items]
Interest rate, stated percentage	5.65%
Debt Instrument, Maturity Date	Mar. 01, 2053
MPLX LP | Senior Notes Due April 2058 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage	4.90%
Debt Instrument, Maturity Date	Apr. 15, 2058

Debt (Schedule of Debt Payments

Debt (Schedule of Debt Payments) (Detail) $ in Millions	Dec. 31, 2024 USD ($)
Debt Disclosure [Abstract]
2025	$ 1,701
2026	1,501
2027	2,001
2028	1,250
2029	$ 750

Debt (Credit Agreements) (Detai

Debt (Credit Agreements) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Debt Instrument, Covenant Description	The MPLX Credit Agreement contains certain representations and warranties, affirmative and restrictive covenants and events of default that MPLX considers 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, including for certain acquisitions and dispositions completed and capital projects undertaken during the relevant period. Other covenants restrict MPLX and/or certain of its subsidiaries from incurring debt, creating liens on our assets and entering into transactions with affiliates.
Debt Instrument, Covenant Compliance	As of December 31, 2024, MPLX was in compliance with the covenants contained in the MPLX Credit Agreement.
MPLX Revolving Credit Facility due July 2027
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 2,000
Debt Instrument, Description of Variable Rate Basis	Adjusted Term SOFR or the Alternate Base Rate, both as defined in the MPLX Credit Agreement, plus an applicable margin
Number of renewals	2
Debt Instrument, Renewal Term	1 year
MPLX Revolving Credit Facility due July 2027 | Maximum
Debt Instrument [Line Items]
Additional borrowing capacity	$ 1,000
MPLX Revolving Credit Facility due July 2027 | Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	150
Revolving Credit Facility
Debt Instrument [Line Items]
Repayments of long-term lines of credit	0	$ 0
Proceeds from long-term lines of credit	$ 0	$ 0

Debt (Senior Notes) (Details)

Debt (Senior Notes) (Details) - USD ($) $ in Millions					12 Months Ended
	Feb. 18, 2025	Dec. 01, 2024	May 20, 2024	Mar. 13, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Feb. 09, 2023
Series B Preferred Stock [Member]
Debt Instrument [Line Items]
Payments for Repurchase of Preferred Stock and Preference Stock					$ 0	$ 600	$ 0
Senior Notes | Senior Note Due June 2034
Debt Instrument [Line Items]
Interest rate, stated percentage			5.50%
Percent of par			98.778%
Debt Instrument, Face Amount			$ 1,650
Debt Instrument, Issuance Date			May 20, 2024
Senior Notes | Senior Notes Due December 2024 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 1,150
Senior Notes | Senior Notes Due March 2033 and March 2053
Debt Instrument [Line Items]
Debt Instrument, Face Amount								$ 1,600
Senior Notes | Senior Note Due March 2033
Debt Instrument [Line Items]
Interest rate, stated percentage								5%
Percent of par								99.17%
Debt Instrument, Face Amount								$ 1,100
Senior Notes | Senior Note Due March 2053
Debt Instrument [Line Items]
Interest rate, stated percentage								5.65%
Percent of par								99.536%
Debt Instrument, Face Amount								$ 500
Senior Notes | Senior Notes Due July 2023 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage				4.50%
Gain (Loss) on Extinguishment of Debt						$ 9
Repayments of Debt				$ 1,000
MPLX LP | Senior Notes | Senior Note Due June 2034
Debt Instrument [Line Items]
Interest rate, stated percentage					5.50%
MPLX LP | Senior Notes | Senior Notes Due December 2024 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage		4.875%			4.875%
Repayments of Debt		$ 1,149
MPLX LP | Senior Notes | Senior Notes Due February 2025 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage					4%
MPLX LP | Senior Notes | Senior Notes Due February 2025 [Member] | Forecast
Debt Instrument [Line Items]
Interest rate, stated percentage	4%
Repayments of Debt	$ 500
MPLX LP | Senior Notes | Senior Note Due March 2033
Debt Instrument [Line Items]
Interest rate, stated percentage					5%
MPLX LP | Senior Notes | Senior Note Due March 2053
Debt Instrument [Line Items]
Interest rate, stated percentage					5.65%
MarkWest | Senior Notes | Senior Notes Due December 2024 [Member]
Debt Instrument [Line Items]
Interest rate, stated percentage		4.875%
Repayments of Debt		$ 1

Net Interest and Other Financ_3

Net Interest and Other Financial Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest expense	$ 963	$ 912	$ 852
Interest income	95	43	4
Net interest and other financial costs	921	923	925
Interest costs capitalized	(19)	(15)	(9)
Related Party
Interest Expense, Other	0	0	5
Nonrelated Party
Interest Expense, Other	$ 72	$ 69	$ 81

Revenue Disaggregation of Reven

Revenue Disaggregation of Revenue (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		$ 9,189	$ 8,733	$ 8,924
Non-ASC 606 revenue(1)	[1]	2,744	2,548	2,689
Total revenues and other income		11,933	11,281	11,613
Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		2,770	2,539	2,359
Revenue from Contract with Customer, Related Parties		4,180	3,985	3,754
Service, Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		357	294	394
Product [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		1,657	1,665	2,219
Revenue from Contract with Customer, Related Parties		225	250	198
Crude Oil and Products Logistics [Member]
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		4,561	4,353	4,076
Crude Oil and Products Logistics [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		391	369	320
Revenue from Contract with Customer, Related Parties		4,152	3,966	3,737
Crude Oil and Products Logistics [Member] | Service, Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		0	0	0
Crude Oil and Products Logistics [Member] | Product [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		5	5	6
Revenue from Contract with Customer, Related Parties		13	13	13
Natural Gas & NGL Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues from contracts with customers		4,628	4,380	4,848
Natural Gas & NGL Services [Member] | Service [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		2,379	2,170	2,039
Revenue from Contract with Customer, Related Parties		28	19	17
Natural Gas & NGL Services [Member] | Service, Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		357	294	394
Natural Gas & NGL Services [Member] | Product [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Third parties		1,652	1,660	2,213
Revenue from Contract with Customer, Related Parties		$ 212	$ 237	$ 185
[1]Non-ASC 606 Revenue includes rental income, sales-type lease revenue, income from equity method investments, and other income.

Revenue Contract Balance Rollfo

Revenue Contract Balance Rollforward (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Beginning Balance Contract with Customer, Asset, Gross		$ 3	$ 21
Contract with Customer, Asset Increase (Decrease)		0	(18)
Contract with Customer, Asset, Reclassified to Receivable	[1]	(1)	0
Ending Balance Contract with Customer, Asset, Gross		2	3
Contract with Customer, Asset Increase (Decrease), Noncurrent		(1)	0
Contract with Customer, Non Current Asset Reclassified to Receivable	[1]	0	0
Contract with Customer, Asset, before Allowance for Credit Loss, Noncurrent		0	1	$ 1
Beginning Balance Deferred Revenue, Noncurrent		347
Ending Balance Deferred Revenue, Noncurrent		317	347
Contract Liability, Noncurrent, Revenue Recognized	[1]		0
Contract Liability, Noncurrent, Period Increase (Decrease) [Line Items]			(2)
Contract with Customer, Liability, Noncurrent			0	2
Contract with Customer, Liability, Change in Timeframe, Performance Obligation Satisfied, Revenue Recognized		0	0
Nonrelated Party
Beginning Balance Deferred Revenue, Current		59	57
Deferred Revenue, Additions		86	42
Deferred Revenue, Revenue Recognized	[1]	(61)	(40)
Ending Balance Deferred Revenue, Current		84	59
Beginning Balance Deferred Revenue, Noncurrent		344	216
Deferred Revenue, Noncurrent, Period Increase (Decrease)		(29)	128
Deferred Revenue, Noncurrent, Revenue Recognized	[1]	0	0
Ending Balance Deferred Revenue, Noncurrent		315	344
Related Party
Beginning Balance Deferred Revenue, Current		81
Deferred Revenue, Additions		90	86
Deferred Revenue, Revenue Recognized	[1]	(66)	(102)
Ending Balance Deferred Revenue, Current		106	81
Deferred Revenue from Contracts with Customers, Current		71	47	63
Beginning Balance Deferred Revenue, Noncurrent		99
Deferred Revenue, Noncurrent, Period Increase (Decrease)		15	4
Deferred Revenue, Noncurrent, Revenue Recognized	[1]	0	0
Ending Balance Deferred Revenue, Noncurrent		110	99
Deferred Revenue from Contracts with Customers, Noncurrent		$ 44	$ 29	$ 25
[1]No significant revenue was recognized related to past performance obligations in the current periods.

Revenue Remaining Performance O

Revenue Remaining Performance Obligations (Details) $ in Millions	Dec. 31, 2024 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 7,400
Contract with Customer, Liability	514
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 2,200
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 2,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 1,800
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 600
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 300
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 500
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	14 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2043-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	19 years

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022
Supplemental Cash Flow Information [Abstract]
Interest paid (net of amounts capitalized)	$ 940		$ 893		$ 813
Income taxes paid	6		7		3
Payments on operating leases	71		71		73
Principal payments under finance lease obligations	1		1		2
Non-cash investing and financing activities:
Net transfers of property, plant and equipment (to)/from materials and supplies inventories	0		(8)		(1)
ROU assets obtained in exchange for new operating lease obligations	47		21		78
ROU assets obtained in exchange for new finance lease obligations	1		0		1
Book Value of Equity Method Investment	$ 4	[1]	$ 311	[1]	$ 0
[1]Represents the book value of MPLX’s equity method investment in OCC in 2024 and Torñado in 2023 prior to MPLX buying out the remaining interest in these entities. See Note 4 for additional information.

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information - Summary of Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Supplemental Cash Flow Information [Abstract]
Additions to property, plant and equipment	$ 1,056	$ 937	$ 806
(Decrease)/Increase in capital accruals	(6)	82	47
Capital Expenditure	$ 1,050	$ 1,019	$ 853

Leases Lessee Disclosures (Deta

Leases Lessee Disclosures (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Right of use assets, net		$ 273	$ 264
Operating Lease, Liability, Noncurrent		217	211
Finance Lease, Liability	[1]	6	$ 6
Finance Lease, Liability, to be Paid, Year One		2
Finance Lease, Liability, to be Paid, Year Two		2
Finance Lease, Liability, to be Paid, Year Three		1
Finance Lease, Liability, to be Paid, Year Four		0
Finance Lease, Liability, to be Paid, Year Five		0
Finance Lease, Liability, to be Paid, after Year Five		7
Finance Lease, Liability, Payment, Due		12
Finance Lease, Liability, Undiscounted Excess Amount		$ 6
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]		Long-term debt due within one year	Long-term debt due within one year
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]		Long-term debt	Long-term debt
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]		Long-term debt, Long-term debt due within one year	Long-term debt, Long-term debt due within one year
Nonrelated Party
Lessee, Lease, Description [Line Items]
Operating lease costs		$ 58	$ 56	$ 61
Finance Lease, Right-of-Use Asset, Amortization		1	1	1
Finance Lease, Interest Expense		0	0	1
Finance Lease Cost		1	1	2
Variable lease cost		12	10	16
Short-term lease cost		71	61	45
Total lease cost		142	128	124
Right of use assets, net		273	264
Operating lease liabilities		45	45
Operating Lease, Liability, Noncurrent		217	211
Operating Lease, Liability		$ 262	$ 256
Operating Lease, Weighted Average Remaining Lease Term		8 years	9 years
Operating Lease, Weighted Average Discount Rate, Percent		4.20%	4.20%
Finance Lease, Right-of-Use Asset, before Accumulated Amortization		$ 10	$ 10
Finance Lease, Right-of-Use Asset, Accumulated Amortization		5	5
Finance Lease, Right-of-Use Asset, after Accumulated Amortization		5	5
Finance Lease, Liability, Current		1	1
Finance Lease, Liability, Noncurrent		5	5
Finance Lease, Liability		$ 6	$ 6
Finance Lease, Weighted Average Remaining Lease Term		22 years	20 years
Finance Lease, Weighted Average Discount Rate, Percent		6%	6%
Lessee, Operating Lease, Liability, to be Paid, Year One		$ 55
Lessee, Operating Lease, Liability, to be Paid, Year Two		48
Lessee, Operating Lease, Liability, to be Paid, Year Three		40
Lessee, Operating Lease, Liability, to be Paid, Year Four		37
Lessee, Operating Lease, Liability, to be Paid, Year Five		30
Lessee, Operating Lease, Liability, to be Paid, after Year Five		97
Lessee, Operating Lease, Liability, to be Paid		307
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		45
Related Party
Lessee, Lease, Description [Line Items]
Operating lease costs		14	$ 14	15
Finance Lease, Right-of-Use Asset, Amortization		0	0	0
Finance Lease, Interest Expense		0	0	0
Finance Lease Cost		0	0	0
Variable lease cost		4	4	2
Short-term lease cost		1	1	0
Total lease cost		19	19	$ 17
Right of use assets, net		226	227
Operating Lease Liability, Current, Related Party		2	1
Operating lease liabilities		2	1
Operating Lease, Liability, Noncurrent, Related Party		224	226
Operating Lease, Liability, Related Party		$ 226	$ 227
Operating Lease, Weighted Average Remaining Lease Term		42 years	43 years
Operating Lease, Weighted Average Discount Rate, Percent		5.80%	5.80%
Lessee, Operating Lease, Liability, to be Paid, Year One		$ 15
Lessee, Operating Lease, Liability, to be Paid, Year Two		15
Lessee, Operating Lease, Liability, to be Paid, Year Three		14
Lessee, Operating Lease, Liability, to be Paid, Year Four		14
Lessee, Operating Lease, Liability, to be Paid, Year Five		14
Lessee, Operating Lease, Liability, to be Paid, after Year Five		532
Lessee, Operating Lease, Liability, to be Paid		604
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		$ 378
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Remaining Lease Term		94 years
Lessee, Operating Lease, Renewal Term		50 years
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Remaining Lease Term		1 year
Lessee, Operating Lease, Renewal Term		1 year
[1]See Note 21 for lease information.

Leases Lessor Disclosures (Deta

Leases Lessor Disclosures (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024		Dec. 31, 2023	Dec. 31, 2022
Lessor, Lease, Description [Line Items]
Sales-type lease revenue, related parties		$ 475		$ 500	$ 465
Sales-type lease revenue		136		136	62
Sales-type Lease, Lease Receivable	[1]	1,814
Sales-type Lease, Unguaranteed Residual Asset	[2]	284
Contributions		34		31	82
Lessor, Operating Lease, Payment to be Received, Year One		857
Lessor, Operating Lease, Payment to be Received, Year Two		811
Lessor, Operating Lease, Payment to be Received, Year Three		673
Lessor, Operating Lease, Payment to be Received, Year Four		379
Lessor, Operating Lease, Payment to be Received, Year Five		228
Lessor, Operating Lease, Payment to be Received, after Year Five		449
Lessor, Operating Lease, Payments to be Received		3,397
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year One		668
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Two		636
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Three		528
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Four		245
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Five		186
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, after Year Five		1,015
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received		3,278
Sales-type and Direct Financing Leases, Lease Receivable, Undiscounted Excess Amount		1,464
Net Investment in Lease, before Allowance for Credit Loss, Current	[3]	306
Net Investment in Lease, before Allowance for Credit Loss, Noncurrent	[2]	1,508
Sales-Type Lease, Net Investment in Lease, before Allowance for Credit Loss		2,098
Property Subject to or Available for Operating Lease, Gross		4,851		4,720
Accumulated depreciation		2,378		2,124
Property, Plant and Equipment, Net		2,473		2,596
Net Investment in Lease, Purchase		159		85	72
Pipelines And Related Assets [Member]
Lessor, Lease, Description [Line Items]
Property Subject to or Available for Operating Lease, Gross		689		677
Refining Logistics and related assets [Member]
Lessor, Lease, Description [Line Items]
Property Subject to or Available for Operating Lease, Gross		1,430		1,399
Terminals and related assets [Member]
Lessor, Lease, Description [Line Items]
Property Subject to or Available for Operating Lease, Gross		1,310		1,267
Marine [Member]
Lessor, Lease, Description [Line Items]
Property Subject to or Available for Operating Lease, Gross		126		126
Gas Gathering And Transportation [Member]
Lessor, Lease, Description [Line Items]
Property Subject to or Available for Operating Lease, Gross		86		86
Processing and fractionation [Member]
Lessor, Lease, Description [Line Items]
Property Subject to or Available for Operating Lease, Gross		1,039		1,000
Land Building Office Equipment And Other [Member]
Lessor, Lease, Description [Line Items]
Property Subject to or Available for Operating Lease, Gross		171		165
Marathon Petroleum Corporation [Member] | Gain (loss) on sales-type lease | Limited Partners Common Units
Lessor, Lease, Description [Line Items]
Contributions	[4]			43
Nonrelated Party
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income		251		243	327
Sales-type Lease, Interest Income		114		114	46
Sales-type Lease, Variable Lease Income		22		22	16
Sales-type lease revenue		136		136	62
Sales-type Lease, Lease Receivable		933	[1]	914
Sales-type Lease, Unguaranteed Residual Asset		95	[2]	63
Sales Type Lease Derecognition Properties And Equipment Net				745
Sales Type Lease Derecognition of Deferred Revenue				277
Sales-type Lease, Selling Profit (Loss)	[5]			509
Lessor, Operating Lease, Payment to be Received, Year One		98
Lessor, Operating Lease, Payment to be Received, Year Two		77
Lessor, Operating Lease, Payment to be Received, Year Three		55
Lessor, Operating Lease, Payment to be Received, Year Four		47
Lessor, Operating Lease, Payment to be Received, Year Five		46
Lessor, Operating Lease, Payment to be Received, after Year Five		214
Lessor, Operating Lease, Payments to be Received		537
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year One		172
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Two		157
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Three		147
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Four		138
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Five		130
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, after Year Five		896
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received		1,640
Sales-type and Direct Financing Leases, Lease Receivable, Undiscounted Excess Amount		707
Net Investment in Lease, before Allowance for Credit Loss, Current	[3]	102
Net Investment in Lease, before Allowance for Credit Loss, Noncurrent	[2]	831
Sales-Type Lease, Net Investment in Lease, before Allowance for Credit Loss		1,028
Related Party
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income		853		822	763
Sales-type Lease, Interest Income		455		467	447
Sales-type Lease, Variable Lease Income		20		33	18
Sales-type lease revenue, related parties		475		500	$ 465
Sales-type Lease, Lease Receivable	[1]	881
Sales-type Lease, Unguaranteed Residual Asset		189	[2]	126
Lessor, Operating Lease, Payment to be Received, Year One		759
Lessor, Operating Lease, Payment to be Received, Year Two		734
Lessor, Operating Lease, Payment to be Received, Year Three		618
Lessor, Operating Lease, Payment to be Received, Year Four		332
Lessor, Operating Lease, Payment to be Received, Year Five		182
Lessor, Operating Lease, Payment to be Received, after Year Five		235
Lessor, Operating Lease, Payments to be Received		2,860
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year One		496
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Two		479
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Three		381
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Four		107
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Five		56
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, after Year Five		119
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received		1,638
Sales-type and Direct Financing Leases, Lease Receivable, Undiscounted Excess Amount		757
Net Investment in Lease, before Allowance for Credit Loss, Current		204	[3]	149
Net Investment in Lease, before Allowance for Credit Loss, Noncurrent		677	[2]	789
Sales-Type Lease, Net Investment in Lease, before Allowance for Credit Loss		$ 1,070
Affiliated Entity
Lessor, Lease, Description [Line Items]
Sales-type Lease, Lease Receivable				87
Sales-type Lease, Unguaranteed Residual Asset				6
Sales Type Lease Derecognition Properties And Equipment Net				50
Sales Type Lease Derecognition of Deferred Revenue				$ 0
Maximum
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Renewal Term		5 years
Maximum | Lease Agreements, Lessor [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Term of Contract		11 years
Minimum
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Renewal Term		1 year
Minimum | Lease Agreements, Lessor [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Term of Contract		1 year
[1]This amount does not include the unguaranteed residual assets[2]The related-party balance is presented in Noncurrent assets - related parties and the third-party balance is presented in Other noncurrent assets in the Consolidated Balance Sheets.[3]The related-party balance is presented in Current assets - related parties and the third-party balance is presented in Receivables, net in the Consolidated Balance Sheets.[4]The amount recognized on commencement date was recorded as a Contribution from MPC in the Consolidated Statements of Equity given the underlying agreements are between entities under common control.[5]The amount recognized on commencement date was recorded as a gain in Other income in the Consolidated Statements of Income.

Commitments and Contingencies_2

Commitments and Contingencies (Detail) - USD ($) $ in Millions		1 Months Ended
	Dec. 15, 2020	Jul. 31, 2020	Dec. 31, 2024	Dec. 31, 2023
Commitments And Contingencies [Line Items]
Accrual for environmental loss contingencies			$ 15	$ 19
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]			Other Liabilities, Current, Other Long-term Liabilities	Other Liabilities, Current, Other Long-term Liabilities
Loss Contingency, Damages Sought, Value		$ 187
Loss Contingency, Damages Paid, Value	$ 4
Capital Addition Purchase Commitments
Commitments And Contingencies [Line Items]
Contractual commitments to acquire property, plant and equipment			$ 128
Indirect Ownership Interest | Bakken Pipeline System | Crude Oil and Products Logistics [Member]
Commitments And Contingencies [Line Items]
Equity Method Investment, Ownership Percentage			9.19%
Financial Guarantee | Bakken Pipeline System | Guarantee of Indebtedness of Others
Commitments And Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted			$ 78
Performance Guarantee | WPC Parent, LLC
Commitments And Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted			$ 82

Commitments and Contingencies_3

Commitments and Contingencies (Minimum Future Payments) (Details) - Minimum Committed Volume Contracts [Member] $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)
Other Commitments [Line Items]
2025	$ 166
2026	152
2027	136
2028	125
2029	87
2030 and thereafter	9
Total	$ 675
Minimum
Other Commitments [Line Items]
Term Of Agreements	1 year
Maximum
Other Commitments [Line Items]
Term Of Agreements	7 years