MPLX LP, 10-Q filed on 11/3/2026
Quarterly Report
v3.26.3
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2026
Oct. 29, 2026
Cover [Abstract]    
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q3  
Entity Central Index Key 0001552000  
Current Fiscal Year End Date --12-31  
Amendment Flag false  
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2026  
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  
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 Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Partnership, Units Outstanding   1,013,027,039
v3.26.3
Consolidated Statements of Income - USD ($)
shares in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Revenues and other income:        
Sales-type lease revenue $ 51 $ 37 $ 139 $ 110
Sales-type lease revenue - related parties 77 113 264 344
Income from equity method investments 282 186 644 542
Gain on equity method investments 0 484 0 484
Total revenues and other income 3,605 3,619 9,955 9,746
Costs and expenses:        
Cost of revenues (excludes items below) 411 395 1,218 1,153
Purchased product costs 734 493 1,819 1,384
Purchases - related parties 418 396 1,224 1,234
Depreciation and amortization [1] 378 346 1,101 996
General and administrative expenses 130 126 352 345
Other taxes 35 36 105 101
Total costs and expenses 2,129 1,818 5,887 5,286
Income from operations 1,476 1,801 4,068 4,460
Net interest and other financial costs 300 243 880 706
Income before income taxes 1,176 1,558 3,188 3,754
Provision for income taxes 2 3 5 5
Net income 1,174 1,555 3,183 3,749
Less: Net income attributable to noncontrolling interests 10 10 30 30
Net income attributable to MPLX LP [2] $ 1,164 $ 1,545 $ 3,153 $ 3,719
Net income attributable to MPLX LP per limited partner unit:        
Common - basic $ 1.15 $ 1.52 $ 3.11 $ 3.65
Common - diluted $ 1.15 $ 1.52 $ 3.11 $ 3.65
Weighted average limited partner units outstanding:        
Common - basic 1,014 1,019 1,014 1,020
Common - diluted 1,014 1,019 1,015 1,020
Nonrelated Party [Member]        
Revenues and other income:        
Rental income $ 66 $ 68 $ 198 $ 196
Other Income 4 4 17 19
Costs and expenses:        
Rental cost of sales 18 22 56 61
Related Party [Member]        
Revenues and other income:        
Rental income 290 228 807 655
Other Income 47 40 134 121
Costs and expenses:        
Rental cost of sales 5 4 12 12
Service [Member]        
Revenues and other income:        
Revenue from Contract with Customer, Excluding Assessed Tax - Third parties 740 750 2,154 2,153
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 1,185 1,094 3,419 3,253
Service, Other [Member]        
Revenues and other income:        
Revenue from Contract with Customer, Excluding Assessed Tax - Third parties 46 [3] 64 135 [3] 233
Product [Member]        
Revenues and other income:        
Revenue from Contract with Customer, Excluding Assessed Tax - Third parties 669 [3] 525 1,703 [3] 1,510
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties $ 148 $ 26 $ 341 $ 126
[1] Depreciation and amortization attributable to Crude Oil and Products Logistics was $154 million and $443 million for the three and nine months ended September 30, 2026, respectively, and $139 million and $407 million for the three and nine months ended September 30, 2025, respectively. Depreciation and amortization attributable to Natural Gas and NGL Services was $224 million and $658 million for the three and nine months ended September 30, 2026, respectively, and $207 million and $589 million for the three and nine months ended September 30, 2025, respectively.
[2] Allocation of net income attributable to MPLX LP assumes all earnings for the period have been distributed based on the distribution priorities applicable to the period.
[3] Contains non-ASC 606 revenue from derivative-related activity as disclosed in Note 11.
v3.26.3
Consolidated Statements of Comprehensive Income - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Net income $ 1,174 $ 1,555 $ 3,183 $ 3,749
Other Comprehensive Income (Loss), Net of Tax 0 0 0 8
Comprehensive income 1,174 1,555 3,183 3,757
Less comprehensive income attributable to:        
Noncontrolling interests 10 10 30 30
Comprehensive income attributable to MPLX LP $ 1,164 $ 1,545 $ 3,153 $ 3,727
v3.26.3
Consolidated Balance Sheets - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Assets    
Cash and cash equivalents $ 1,297 $ 2,137
Receivables, less allowance for expected credit loss 799 735
Inventories 203 172
Other current assets 41 51
Total current assets 3,396 3,994
Equity method investments 5,446 4,798
Property, plant and equipment, net 23,082 21,698
Intangibles, net 1,276 1,397
Goodwill 8,736 8,755
Right of use assets, net 248 276
Other noncurrent assets 1,230 1,125
Total assets 44,184 43,005
Liabilities    
Accounts payable 200 108
Accrued liabilities 374 254
Accrued property, plant and equipment 566 438
Long-term debt due within one year 2 1,502
Accrued interest payable 313 354
Operating lease liabilities 53 53
Total current liabilities 2,175 3,249
Long-term deferred revenue 107 119
Long-term debt 26,606 24,151
Deferred income taxes 26 25
Long-term operating lease liabilities 192 217
Total liabilities 29,893 28,477
Commitments and contingencies (see Note 17)
Equity    
Accumulated other comprehensive income 5 5
Total MPLX LP partners’ capital 14,067 14,301
Noncontrolling interests 224 227
Total equity 14,291 14,528
Total liabilities and equity 44,184 43,005
Related Party [Member]    
Assets    
Current assets - related parties 1,056 899
Other current assets 1 1
Right of use assets, net 238 239
Noncurrent assets - related parties 770 962
Liabilities    
Other current liabilities 474 399
Operating lease liabilities 2 2
Other long-term liabilities 415 364
Equity    
Limited Partners' Capital Account 4,803 4,845
Nonrelated Party [Member]    
Liabilities    
Other current liabilities 193 141
Other long-term liabilities 372 352
Equity    
Limited Partners' Capital Account $ 9,259 $ 9,451
v3.26.3
Consolidated Balance Sheets (Parenthetical) - shares
Sep. 30, 2026
Dec. 31, 2025
Units Outstanding 1,013,208,863 1,015,702,040
Common Unit-holders Public | Nonrelated Party [Member]    
Units Outstanding 366,000,000 368,000,000
Common Unit-holders Public | Related Party [Member]    
Units Outstanding 647,000,000 647,000,000
v3.26.3
Consolidated Statements of Cash Flows - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Operating activities:    
Net income $ 3,183 $ 3,749
Adjustments to reconcile net income to net cash provided by operating activities:    
Amortization of deferred financing costs and debt discount 23 23
Depreciation and amortization [1] 1,101 996
Deferred income taxes 0 1
Business Combination, Achieved in Stages, Preacquisition Equity Interest in Acquiree, Remeasurement, Gain 0 (484)
(Gain)/loss on disposal of assets 2 (1)
Income from equity method investments (644) (542)
Distributions from unconsolidated affiliates 685 631
Changes in derivative assets and liabilities 38 (7)
Changes in:    
Current receivables (23) 44
Inventories (32) (19)
Current liabilities and other current assets 209 (38)
Assets and liabilities - related parties (17) 105
Right of use assets and operating lease liabilities 4 3
Deferred revenue (5) (52)
All other, net 2 4
Net cash provided by operating activities 4,526 4,413
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]    
Additions to property, plant and equipment (2,195) (1,094)
Acquisitions, net of cash acquired (14) 3,316
Disposal of assets 12 1
Investments - acquisitions and contributions 720 776
Investments - redemptions, repayments, return of capital and sales proceeds 32 143
Payment for (Proceeds from) Other Investing Activity 4 108
Net cash used in investing activities (2,853) (4,934)
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]    
Long-term debt borrowings 3,716 6,541
Long-term debt - repayments (2,756) (2,464)
Debt issuance costs 36 62
Unit repurchases [2] (150) (300)
Distributions to noncontrolling interests 33 33
Distributions to LP unitholders (3,277) (2,923)
Contributions from MPC 24 20
All other, net (1) (6)
Net cash provided by (used in) financing activities (2,513) 767
Net change in cash, cash equivalents and restricted cash (840) 246
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance 2,137 1,519
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Ending Balance 1,297 1,765
Revolving Credit Facility    
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]    
Related party debt borrowings 231 50
Related party debt repayments (231) (50)
Series A Preferred Stock [Member]    
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]    
Distributions to Series A preferred unitholders $ 0 $ 6
[1] Depreciation and amortization attributable to Crude Oil and Products Logistics was $154 million and $443 million for the three and nine months ended September 30, 2026, respectively, and $139 million and $407 million for the three and nine months ended September 30, 2025, respectively. Depreciation and amortization attributable to Natural Gas and NGL Services was $224 million and $658 million for the three and nine months ended September 30, 2026, respectively, and $207 million and $589 million for the three and nine months ended September 30, 2025, respectively.
[2] Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.
v3.26.3
Consolidated Statements of Equity and Series A Preferred Units (Consolidated Statements of Equity) - USD ($)
$ in Millions
Total
Common Unit-holders Public
Common Unit-holder MPC
Accumulated Other Comprehensive Income
Non-controlling Interests
Beginning Balance at Dec. 31, 2024 $ 13,807 $ 9,322 $ 4,257 $ (3) $ 231
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Net income 1,136 410 716 0 10
Unit repurchases (100) (100) 0 0 0
Conversion of Series A preferred units 197 197 0 0 0
Distributions (983) (353) (619) 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders         (11)
Contributions 7 0 7 0 0
Other 4 (4) 0 8 0
Ending Balance at Mar. 31, 2025 14,068 9,472 4,361 5 230
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Net income 1,058 384 664 0 10
Unit repurchases (100) (100) 0 0 0
Distributions (987) (357) (619) 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders         (11)
Contributions 7 0 7 0 0
Other 3 3 0 0 0
Ending Balance at Jun. 30, 2025 14,049 9,402 4,413 5 229
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Net income 1,555 563 982 0 10
Unit repurchases (100) (100) 0 0 0
Distributions (986) (355) (620) 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders         (11)
Contributions 2 0 2 0 0
Other 4 3 1 0 0
Ending Balance at Sep. 30, 2025 14,524 9,513 4,778 5 228
Beginning Balance at Dec. 31, 2025 14,528 9,451 4,845 5 227
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Net income 922 330 582 0 10
Unit repurchases (50) (50) 0 0 0
Distributions (1,104) (396) (697) 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders         (11)
Contributions 4 0 4 0 0
Other (3) (3) 0 0 0
Ending Balance at Mar. 31, 2026 14,297 9,332 4,734 5 226
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Net income 1,087 390 687 0 10
Unit repurchases (50) (50) 0 0 0
Distributions (1,103) (395) (697) 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders         (11)
Contributions 18 0 18 0 0
Other 3 4 (1) 0 0
Ending Balance at Jun. 30, 2026 14,252 9,281 4,741 5 225
Increase (Decrease) in Stockholders' Equity [Roll Forward]          
Net income 1,174 421 743 0 10
Unit repurchases (50) (50) 0 0 0
Distributions (1,103) (395) (697) 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders         (11)
Contributions 15 0 15 0 0
Other 3 2 1 0 0
Ending Balance at Sep. 30, 2026 $ 14,291 $ 9,259 $ 4,803 $ 5 $ 224
v3.26.3
Consolidated Statements of Equity and Series A Preferred Units (Temporary Equity)
$ in Millions
Series A Preferred Unit-holders
USD ($)
Beginning Balance at Dec. 31, 2024 $ 203
Net income 0
Conversion of Series A preferred units (197)
Distributions 6
Ending Balance at Mar. 31, 2025 0
Net income 0
Distributions 0
Ending Balance at Jun. 30, 2025 0
Net income 0
Distributions 0
Ending Balance at Sep. 30, 2025 0
Beginning Balance at Dec. 31, 2025 0
Net income 0
Distributions 0
Ending Balance at Mar. 31, 2026 0
Net income 0
Distributions 0
Ending Balance at Jun. 30, 2026 0
Net income 0
Distributions 0
Ending Balance at Sep. 30, 2026 $ 0
v3.26.3
Description of the Business and Basis of Presentation
 9 Months Ended
Sep. 30, 2026
Accounting Policies [Abstract]  
Business Description and Basis of Presentation 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. We are engaged in the gathering, transportation, storage and distribution of crude oil, refined products, other hydrocarbon-based products and renewables; the gathering, treating, 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.
Refer to Note 8 for additional information about our operations.
Basis of Presentation
These interim consolidated financial statements are unaudited; however, in the opinion of MPLX’s management, these statements reflect all adjustments necessary for a fair statement of the results for the periods reported. All such adjustments are of a normal, recurring nature unless otherwise disclosed. These interim consolidated financial statements, including the notes, have been prepared in accordance with the rules and regulations of the SEC applicable to interim period financial statements and do not include all of the information and disclosures required by GAAP for complete financial statements. Certain information derived from our audited annual financial statements, prepared in accordance with GAAP, has been condensed or omitted from these interim financial statements.
These interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2025. The results of operations for the three and nine months ended September 30, 2026 are not necessarily indicative of the results to be expected for the full year.
MPLX’s 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.
v3.26.3
Accounting Standards
 9 Months Ended
Sep. 30, 2026
Accounting Standards Update and Change in Accounting Principle [Abstract]  
Accounting Standards Accounting Standards
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 face of 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 in this ASU 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.
v3.26.3
Acquisitions and Other Transactions
 9 Months Ended
Sep. 30, 2026
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]  
Acquisitions and Other Transactions Acquisitions and Other Transactions
Northwind Midstream Acquisition
On August 29, 2025, MPLX completed the acquisition of 100 percent of the outstanding membership interests of Northwind Delaware Holdings LLC (“Northwind Midstream”) for $2.4 billion in cash (the “Northwind Midstream Acquisition”). Northwind Midstream provides sour gas gathering and treating services in Lea County, New Mexico, which enhances MPLX’s Permian natural gas and NGL value chain. The Northwind Midstream Acquisition was financed with a portion of the net proceeds from MPLX's $4.5 billion senior notes issued in August 2025.
Northwind Midstream consists of over 200,000 dedicated acres, more than 200 miles of gathering pipelines, two in-service acid gas injection wells at 20 MMcf/d and a third permitted well that will bring its total capacity to 37 MMcf/d. At the time of acquisition, the system had 150 MMcf/d of sour gas treating capacity, with in-process expansion projects expected to increase capacity to over 400 MMcf/d by the second half of 2026. The system is partially supported by minimum volume commitments by regional producers.
The Northwind Midstream Acquisition was accounted for as a business combination requiring all Northwind Midstream assets and liabilities to be remeasured to fair value. The fair value of property, plant and equipment was based primarily on the cost approach. The fair value of the identifiable intangible assets was primarily based on the multi-period excess earnings method, which is an income approach. The intangible assets acquired are related to various commercial contracts with a weighted average amortization period of 15 years. The following table reflects our allocation of the $2.4 billion purchase price to the Northwind Midstream assets and liabilities, as well as measurement period adjustments since the acquisition date:
(In millions)August 29,
2025		AdjustmentsAs adjusted
Assets acquired:
Cash and cash equivalents$17 $— $17 
Receivables11 — 11 
Other current assets1 — 1 
Property, plant and equipment1,182 (15)1,167 
Intangibles951 6 957 
Other noncurrent assets2 — 2 
Total assets acquired2,164 (9)2,155 
Liabilities assumed:
Accounts payable15 7 22 
Accrued property, plant and equipment84 (2)82 
Accrued liabilities6 4 10 
Other current liabilities1 — 1 
Long-term operating lease liabilities1 — 1 
Total liabilities assumed107 9 116 
Total identifiable net assets2,057 (18)2,039 
Goodwill356 4 360 
Fair value of net assets acquired$2,413 $(14)$2,399 
The purchase price allocation, inclusive of measurement period adjustments, resulted in the recognition of $360 million in goodwill by our Natural Gas and NGL Services segment, all of which is deductible for tax purposes. Goodwill represents the accelerated growth opportunities in the Permian using Northwind Midstream's asset base, which is complementary and adjacent to MPLX's existing Delaware basin natural gas system and offers optionality to direct volumes through our integrated system. The results for the acquired business are reported within our Natural Gas and NGL Services segment.
Pro forma financial information assuming the Northwind Midstream 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.
Divestiture of Rockies Operations
On November 12, 2025, MPLX completed the sale of its Rockies gathering and processing operations (the “Rockies”) to a subsidiary of Harvest Midstream for $980 million in cash. The sale of these non-core gathering and processing assets did not represent a strategic shift that has or will have a material effect on our operations or financial results. Prior to the sale, the Rockies operations were reported within the Natural Gas and NGL Services segment.
BANGL, LLC Acquisition
On July 1, 2025, MPLX purchased the remaining 55 percent interest in BANGL, LLC (“BANGL”) for $703 million in cash, plus an earnout provision of up to $275 million based on targeted EBITDA growth from 2026 to 2029 (the “BANGL Acquisition”). We recorded a liability for these contingent payments in the third quarter of 2025. See Note 10 for additional details on the inputs used to measure the fair value of these contingent payments. On July 3, 2025, MPLX used cash on hand to extinguish approximately $656 million principal amount of debt outstanding, including interest, related to certain term and revolving loans assumed as part of the BANGL Acquisition.
Upon completion of the BANGL Acquisition, our existing equity investment was remeasured to fair value resulting in the recognition of a $484 million gain, which is included in Gain on equity method investments within the accompanying Consolidated Statements of Income. The fair value of the previously held equity method investment was estimated using an income approach, with significant valuation inputs including forecasted cash flows and discount rates ranging from 11 to 12 percent. As a result of the BANGL Acquisition, we now own 100 percent of BANGL and its results are reflected in our Natural Gas and NGL Services segment within our consolidated financial results.
The following table summarizes the purchase price consideration in connection with the BANGL Acquisition:
Total cash paid$703 
Fair value of contingent consideration as of acquisition date234 
Total consideration937 
Fair value of previously held equity interest766 
Fair value of net assets acquired$1,703 
The BANGL Acquisition was accounted for as a business combination requiring all BANGL assets and liabilities to be remeasured to fair value. The fair value of property, plant and equipment was determined using a combination of both the cost and income approach. The fair value of the identifiable intangible assets was primarily based on the multi-period excess earnings method, which is an income approach. The intangible asset acquired is related to a customer relationship with an amortization period of 11 years. The following table reflects our determination of the fair value of the BANGL assets and liabilities:
(In millions)July 1,
2025
Assets acquired:
Cash and cash equivalents$18 
Other current assets4 
Property, plant and equipment1,550 
Intangibles77 
Other noncurrent assets22 
Total assets acquired1,671 
Liabilities assumed:
Long-term debt due within one year46 
Other current liabilities42 
Long-term debt610 
Other long-term liabilities1 
Total liabilities assumed699 
Total identifiable net assets972 
Goodwill731 
Fair value of net assets acquired$1,703 
The purchase price allocation resulted in the recognition of $731 million in goodwill by our Natural Gas and NGL Services segment, 55 percent of which is deductible for tax purposes. Goodwill represents the advancement of our wellhead-to-water strategy by securing full ownership of a strategically located NGL transport asset, which further integrates our midstream infrastructure connecting the Permian and Gulf Coast regions.
Pro forma financial information assuming the BANGL 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.
Matterhorn Express Pipeline Acquisition
On June 16, 2025, MPLX purchased an additional five percent ownership interest in the joint venture that owns and operates the Matterhorn Express pipeline for $151 million, bringing our total interest to 10 percent. The pipeline is designed to transport natural gas from the Permian basin to the Katy area near Houston. The purchase price of the additional five percent ownership interest in the joint venture exceeded the amount of the claim to the underlying net assets of the joint venture by approximately $124 million, with $63 million of this difference attributed to property, plant and equipment and $61 million attributed to customer-related intangibles. The amounts attributed to property, plant and equipment and customer-related intangibles will be amortized to net income over the remaining useful lives of the assets and the weighted average remaining term of the customer contracts, respectively. Our investment in the joint venture that owns and operates the Matterhorn Express pipeline continues to be accounted for as an equity method investment within our Natural Gas and NGL Services segment.
Whiptail Midstream Acquisition
On March 11, 2025, MPLX acquired gathering businesses from Whiptail Midstream, LLC for $235 million in cash. These San Juan basin assets consist primarily of crude and natural gas gathering systems in the Four Corners region, and enhance our strategic relationship with MPC. The acquisition was accounted for as a business combination, which requires all the identifiable assets acquired and liabilities assumed to be remeasured to fair value at the date of acquisition. The final valuation includes $170 million of property, plant and equipment, $41 million of intangibles and $24 million of net working capital. The results for the acquired business are allocated between our two segments based on the product-based value chain the underlying assets support.
v3.26.3
Investments and Noncontrolling Interests
 9 Months Ended
Sep. 30, 2026
Equity Method Investments and Joint Ventures [Abstract]  
Investments and Noncontrolling Interests Equity Method Investments
The following table presents MPLX’s equity method investments at the dates indicated:
Ownership as ofCarrying value at
September 30,September 30,December 31,
(In millions, except ownership percentages)VIE202620262025
Crude Oil and Products Logistics
Illinois Extension Pipeline Company, L.L.C.35%$214 $208 
LOOP LLC41%309 313 
MarEn Bakken Company LLC(1)
25%486 502 
Other(2)
X
17 - 67%
542 558 
Total Crude Oil and Products Logistics
1,551 1,581 
Natural Gas and NGL Services
Eiger Express Holdings, LLCX15%199 34 
MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C.X67%393 407 
MarkWest Utica EMG, L.L.C.X62%992 890 
MXP Parent, LLC10%269 198 
Ohio Gathering Company L.L.C.(3)
X31%426 444 
Sherwood Midstream LLCX50%464 475 
Texas City Logistics LLCX50%409 163 
WPC Parent, LLC30%320 273 
Other(2)
X
10 - 51%
423 333 
Total Natural Gas and NGL Services
3,895 3,217 
Total$5,446 $4,798 
(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, the “Bakken Pipeline system”).
(2)    Included within Other are certain equity method investments that have been deemed to be VIEs.
(3)    MPLX also holds a 43 percent indirect interest in Ohio Gathering Company L.L.C. through our ownership interest in MarkWest Utica EMG, L.L.C.
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 nine months ended September 30, 2026 and September 30, 2025. See Note 17 for information on our guarantees related to equity method investees.
v3.26.3
Related Party Agreements and Transactions
 9 Months Ended
Sep. 30, 2026
Related Party Transactions [Abstract]  
Related Party Agreements and Transactions 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 a marine transportation services agreement. In addition, MPLX has obligations to MPC for services provided to MPLX by MPC under omnibus and employee services agreements as well as various other agreements.
During the second quarter of 2026, a refining logistics agreement between MPLX and MPC was renewed, which required reassessment of the agreement under ASC 842. As a result of the reassessment, the lease was reclassified from sales-type to operating lease (see Note 16).
Related Party Loan
MPLX is party to a loan agreement with MPC (the “MPC Loan Agreement”). 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 is scheduled to expire, and any 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 plus 1.25 percent or such lower rate as would be applicable to such loans under MPLX’s bank revolving credit facility as discussed in Note 12. On October 30, 2026, MPLX and MPC amended and restated the MPC Loan Agreement to increase the borrowing capacity from $1.5 billion to $2.5 billion and to extend the term of the intercompany loan agreement from July 31, 2029, to October 30, 2031.
Activity on the MPC Loan Agreement for the nine months ended September 30, 2026 and September 30, 2025 is summarized below.
Nine Months Ended 
September 30,
(In millions, except %)20262025
Borrowings$231 $50 
Weighted average interest rate of borrowings4.90 %5.68 %
Repayments$231 $50 
Outstanding balance at end of period$— $— 
Related Party Revenue and Other Income
Related party revenue consists primarily of revenue recognized from commercial agreements with MPC as well as fees charged under operating agreements with MPC and our equity affiliates as discussed 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 three and nine months ended September 30, 2026, these sales totaled $436 million and $993 million, respectively. For the three and nine months ended September 30, 2025, these sales totaled $151 million and $476 million, respectively.
See Note 11 for additional details regarding related party derivative activity with MPC.
Related Party Expenses
MPC charges MPLX for executive management services and certain general and administrative services provided to MPLX under the terms of our omnibus agreements (“Omnibus charges”), for certain employee services provided to MPLX under employee services agreements (“ESA charges”) and fees paid under co-location agreements and ground lease agreements. 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 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 three and nine months ended September 30, 2026, General and administrative expenses incurred from MPC totaled $104 million and $274 million, respectively. For the three and nine months ended September 30, 2025, General and administrative expenses incurred from MPC totaled $80 million and $236 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 the three and nine months ended September 30, 2026, these charges totaled $73 million and $190 million, respectively. For the three and nine months ended September 30, 2025, these charges totaled $64 million and $159 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 and deferred revenue.
(In millions)September 30,
2026		December 31,
2025
Current assets - related parties
Receivables$814 $624 
Lease receivables228 269 
Prepaid13 5 
Other1 1 
Total1,056 899 
Noncurrent assets - related parties
Long-term lease receivables243 421 
Right of use assets238 239 
Unguaranteed residual assets243 263 
Long-term receivables46 39 
Total770 962 
Current liabilities - related parties
MPC Loan Agreement and other payables(1)
346 290 
Derivative liabilities25 — 
Deferred revenue101 107 
Operating lease liabilities2 2 
Total474 399 
Long-term liabilities - related parties
Long-term operating lease liabilities235 237 
Long-term deferred revenue180 127 
Total$415 $364 
(1)    There were no borrowings outstanding on the MPC Loan Agreement as of September 30, 2026 or December 31, 2025.
v3.26.3
Equity
 9 Months Ended
Sep. 30, 2026
Equity [Abstract]  
Equity Equity
The changes in the number of common units during the nine months ended September 30, 2026 are summarized below:
(In units)Common Units
Balance at December 31, 20251,015,702,040 
Unit-based compensation awards134,291 
Units redeemed in unit repurchase program(2,627,468)
Balance at September 30, 20261,013,208,863 
Unit Repurchase Program
As of September 30, 2026, we had $970 million remaining under the unit repurchase authorization. Total unit repurchases were as follows for the respective periods:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions, except per unit data)2026202520262025
Number of common units repurchased1 2 3 6 
Cash paid for common units repurchased(1)
$50 $100 $150 $300 
Average cost per unit(1)
$58.69 $50.86 $57.09 $51.20 
(1)    Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.
Series A Redeemable Preferred Unit Conversions
On February 11, 2025, MPLX exercised its right to convert the remaining 6 million outstanding Series A preferred units into common units in accordance with the conversion provision outlined in our Sixth Amended and Restated Agreement of Limited Partnership.
Cash Distributions
On October 27, 2026, MPLX declared a cash distribution for the third quarter of 2026, totaling $1,226 million, or $1.2111 per common unit. This distribution will be paid on November 13, 2026 to common unitholders of record on November 6, 2026. Although our partnership agreement requires that we distribute all of our available cash (as defined in the partnership agreement) each quarter, we do not otherwise have a legal obligation to distribute any particular amount per common unit.
The allocation of total quarterly cash distributions is as follows for the three and nine months ended September 30, 2026 and September 30, 2025. Distributions are not accrued until declared. MPLX’s distributions are declared subsequent to the quarter end; therefore, the following table represents total cash distributions applicable to the period for which the distributions relate as opposed to the quarter in which they were declared and paid.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions, except per unit data)2026202520262025
Distribution declared:
Limited partner units - public$442 $397 $1,232 $1,110 
Limited partner units - MPC784 698 2,178 1,936 
Total distribution declared$1,226 $1,095 $3,410 $3,046 
Quarterly cash distributions declared per limited partner common unit$1.2111 $1.0765 $3.3641 $2.9895 
v3.26.3
Net Income Per Limited Partner Unit
 9 Months Ended
Sep. 30, 2026
Earnings Per Share [Abstract]  
Net Income Per Limited Partner Unit Net Income Per Limited Partner Unit
Net income per unit applicable to common 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 three and nine months ended September 30, 2026 and September 30, 2025, MPLX had participating securities consisting of common units, certain equity-based compensation awards and dilutive potential common units related to certain equity-based compensation awards, and also for the nine months ended September 30, 2025, Series A preferred units. Potential common units that were anti-dilutive, and therefore omitted from the diluted earnings per unit calculation for the three and nine months ended September 30, 2026 and September 30, 2025, were less than one million.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions, except per unit data)2026202520262025
Net income attributable to MPLX LP(1):
$1,164 $1,545 $3,153 $3,719 
Less: Distributed and undistributed earnings allocated to other participating securities1 1 2 2 
Net income available to common unitholders$1,163 $1,544 $3,151 $3,717 
Weighted average units outstanding:
Basic1,014 1,019 1,014 1,020 
Diluted1,014 1,019 1,015 1,020 
Net income attributable to MPLX LP per limited partner unit:
Basic$1.15 $1.52 $3.11 $3.65 
Diluted$1.15 $1.52 $3.11 $3.65 
(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.
v3.26.3
Segment Information
 9 Months Ended
Sep. 30, 2026
Segment Reporting [Abstract]  
Segment Reporting 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. 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, treats, processes and transports natural gas; and transports, fractionates, stores and markets NGLs.
The CODM evaluates the performance of our segments using Segment Adjusted EBITDA. The CODM uses Segment Adjusted EBITDA results and considers forecast-to-actual variances on a periodic basis 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; (vii) transaction-related costs and (viii) 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) 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:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Crude Oil and Products Logistics
Service revenue$1,272 $1,205 $3,679 $3,569 
Rental income298 239 829 682 
Product related revenue5 4 16 12 
Sales-type lease revenue77 113 264 344 
Income from equity method investments83 71 197 186 
Other income33 28 91 94 
Total segment revenues and other income(1)
1,768 1,660 5,076 4,887 
Operating expenses582 553 1,686 1,613 
Other segment items(2)
(18)(30)(86)(98)
Segment Adjusted EBITDA(3)
1,204 1,137 3,476 3,372 
Capital expenditures174 147 409 391 
Investments in unconsolidated affiliates(4)
— 13 — 13 
Natural Gas and NGL Services
Service revenue653 639 1,894 1,837 
Rental income58 57 176 169 
Product related revenue858 611 2,163 1,857 
Sales-type lease revenue 51 37 139 110 
Income from equity method investments199 115 447 356 
Gain on equity method investments(5)
— 484 — 484 
Other income18 16 60 46 
Total segment revenues and other income(1)
1,837 1,959 4,879 4,859 
Purchased product costs734 493 1,819 1,384 
Operating expenses435 426 1,281 1,293 
Other segment items(2)
13 411 (108)341 
Segment Adjusted EBITDA(3)
655 629 1,887 1,841 
Capital expenditures667 447 1,916 812 
Investments in unconsolidated affiliates(4)
$281 $227 $720 $549 
(1)    Within the total segment revenues and other income amounts presented above, third-party revenues for the Crude Oil and Products Logistics segment were $189 million and $508 million for the three and nine months ended September 30, 2026, respectively, and $201 million and $565 million for the three and nine months ended September 30, 2025, respectively. Third-party revenues for the Natural Gas and NGL Services segment were $1,669 million and $4,482 million for the three and nine months ended September 30, 2026, respectively, and $1,917 million and $4,682 million for the three and nine months ended September 30, 2025, 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, 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 three and nine months ended September 30, 2026 and September 30, 2025 include cash contributions to several joint ventures to fund current growth capital projects. Investments in unconsolidated affiliates for the nine months ended September 30, 2025 exclude $151 million related to the acquisition of an additional interest in the joint venture that owns and operates the Matterhorn Express Pipeline, and the three and nine months ended September 30, 2025 exclude a $49 million capital contribution to WPC Parent, LLC to purchase Enbridge’s special membership interest in the Bay Runner Pipeline project and a $13 million payment related to earnout associated with MXP Parent, LLC.
(5)    The three and nine months ended September 30, 2025 represent the gain on remeasurement of our existing equity investment in BANGL in conjunction with the BANGL Acquisition.
The table below provides a reconciliation of Segment Adjusted EBITDA for reportable segments to Net income.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Reconciliation to Net income:
Crude Oil and Products Logistics Segment Adjusted EBITDA
$1,204 $1,137 $3,476 $3,372 
Natural Gas and NGL Services Segment Adjusted EBITDA
655 629 1,887 1,841 
Total reportable segments1,859 1,766 5,363 5,213 
Depreciation and amortization(1)
(378)(346)(1,101)(996)
Gain on equity method investments— 484 — 484 
Net interest and other financial costs(300)(243)(880)(706)
Income from equity method investments282 186 644 542 
Distributions/adjustments related to equity method investments(250)(251)(735)(707)
Transaction-related costs(2)
— (21)— (21)
Adjusted EBITDA attributable to noncontrolling interests11 11 33 33 
Other(3)
(50)(31)(141)(93)
Net income$1,174 $1,555 $3,183 $3,749 
(1)    Depreciation and amortization attributable to Crude Oil and Products Logistics was $154 million and $443 million for the three and nine months ended September 30, 2026, respectively, and $139 million and $407 million for the three and nine months ended September 30, 2025, respectively. Depreciation and amortization attributable to Natural Gas and NGL Services was $224 million and $658 million for the three and nine months ended September 30, 2026, respectively, and $207 million and $589 million for the three and nine months ended September 30, 2025, respectively.
(2)    Transaction-related costs include costs associated with acquisition and divestiture-related activities, including significant transactions discussed in Note 3.
(3)    Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.
v3.26.3
Property, Plant and Equipment
 9 Months Ended
Sep. 30, 2026
Property, Plant, and Equipment [Abstract]  
Property, Plant and Equipment Property, Plant and Equipment
Property, plant and equipment with associated accumulated depreciation is shown below:
September 30, 2026December 31, 2025
(In millions)Gross PP&EAccumulated DepreciationNet PP&EGross PP&EAccumulated DepreciationNet PP&E
Crude Oil and Products Logistics
$14,369 $5,452 $8,917 $13,809 $5,058 $8,751 
Natural Gas and NGL Services
19,696 5,531 14,165 17,950 5,003 12,947 
Total$34,065 $10,983 $23,082 $31,759 $10,061 $21,698 
Depreciation expense was $335 million and $970 million for the three and nine months ended September 30, 2026, respectively, and $310 million and $897 million for the three and nine months ended September 30, 2025, respectively.
v3.26.3
Fair Value Measurements
 9 Months Ended
Sep. 30, 2026
Fair Value Disclosures [Abstract]  
Fair Value Disclosures Fair Value Measurements
Fair Values – Recurring
The following table presents the impact on the Consolidated Balance Sheets of MPLX’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2026 and December 31, 2025 by fair value hierarchy level.
September 30, 2026December 31, 2025
(In millions)Level 1Level 2Level 3Level 1Level 2Level 3
Liabilities:
Embedded derivatives in commodity contracts
Other current liabilities$— $— $13 $— $— $6 
Other long-term liabilities— — 40 — — 35 
Total embedded derivatives in commodity contracts— — 53 — — 41 
Contingent consideration / Other long-term liabilities— — 238 — — 236 
Commodity contracts - related party— 25 — — — — 
Total carrying value in Consolidated Balance Sheets$— $25 $291 $— $— $277 
Level 3 instruments include a liability for contingent consideration related to the BANGL Acquisition earnout provision and an embedded derivative liability for a natural gas purchase commitment embedded in a keep-whole processing agreement.
The fair value calculation for the contingent consideration liability was estimated using discounted cash flows based on a Monte Carlo simulation. Future earnout payments are tied to the achievement of EBITDA growth from 2026 to 2029, which includes the significant unobservable input of forecasted throughput volumes. The earnout payment will continue to be remeasured at fair value each quarter with changes in fair value recognized in earnings until either the EBITDA targets are met or the earnout period ends, with the total payout capped at $275 million.
The fair value calculation for the embedded derivative liability for the natural gas purchase commitment used significant unobservable inputs including: (1) NGL prices interpolated and extrapolated due to inactive markets ranging from $0.64 to $2.04 per gallon with a weighted average of $0.89 per gallon and (2) a 100 percent probability of renewal for the five-year renewal term of the gas purchase commitment and related keep-whole processing agreement. Increases or decreases in the fractionation spread result in an increase or decrease in the fair value of the embedded derivative liability, respectively.
Changes in Level 3 Fair Value Measurements
The following table is a reconciliation of the net beginning and ending balances recorded for net liabilities classified as Level 3 in the fair value hierarchy.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Beginning balance$(282)$(55)$(277)$(58)
Contingent consideration(1)
— (234)— (234)
Unrealized and realized gain/(loss) included in Net income(2)
(13)2 (23)(1)
Settlements4 2 9 8 
Ending balance$(291)$(285)$(291)$(285)
The amount of total gain/(loss) for the period included in earnings attributable to the change in unrealized gain/(loss) relating to liabilities still held at end of period$(12)$2 $(19)$(1)
(1)    Liability recorded in the third quarter of 2025 related to the BANGL Acquisition earnout provision.
(2)    Gain/(loss) on derivatives embedded in commodity contracts are recorded in Purchased product costs in the Consolidated Statements of Income.

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, historical incurrence of credit losses, and expected insignificance of future credit losses, 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 11).
The fair value of MPLX’s debt is estimated based on average bid prices obtained from broker quotes 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:
September 30, 2026December 31, 2025
(In millions)Fair ValueCarrying ValueFair ValueCarrying Value
Outstanding debt(1)
$24,381 $26,797 $24,887 $25,821 
(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.
v3.26.3
Derivative Financial Instruments
 9 Months Ended
Sep. 30, 2026
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Derivative Disclosure Derivatives
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. The probability 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 10.
Related Party Derivatives - MPLX has derivative positions with MPC to partially hedge its direct exposure to commodity price risk in its Natural Gas and NGL Services segment. Changes in the fair value of the derivatives are based on changes in forward price curves for the underlying commodity and recognized in earnings through Product sales and Service revenue - product related, in the Consolidated Statements of Income.
The following table presents the fair value of derivative instruments as of September 30, 2026 and December 31, 2025, and the line items in the Consolidated Balance Sheets in which the fair values are reflected. As of September 30, 2026 and December 31, 2025, there were no derivative assets or liabilities that were offset in the Consolidated Balance Sheets.
(In millions)September 30, 2026December 31, 2025
Commodity derivatives
Current liabilities - related parties$25 $— 
Other current liabilities(1)
13 6 
Other long-term liabilities(1)
40 35 
(1)    Includes embedded derivatives.
The impact of MPLX’s derivative contracts not designated as hedging instruments and the location of gains and losses recognized in the Consolidated Statements of Income is summarized below:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Product sales
Realized loss$(2)$— $(6)$— 
Unrealized loss(2)— (4)— 
Product sales loss(4)— (10)— 
Service revenue - product related
Realized loss(16)— (37)— 
Unrealized loss(9)— (21)— 
Service revenue - product related loss(25)— (58)— 
Purchased product costs
Realized loss(3)(2)(8)(8)
Unrealized gain/(loss)(7)4 (13)7 
Purchased product costs gain/(loss)(10)2 (21)(1)
Total derivative gain/(loss) included in Net income$(39)$2 $(89)$(1)
v3.26.3
Debt
 9 Months Ended
Sep. 30, 2026
Debt Disclosure [Abstract]  
Debt Debt
MPLX’s outstanding borrowings consist of the following:
(In millions)September 30,
2026		December 31,
2025
MPLX LP:
Fixed rate senior notes$26,969 $25,969 
Consolidated subsidiaries:
ANDX31 31 
Finance lease obligations5 6 
Total27,005 26,006 
Unamortized debt issuance costs(194)(174)
Unamortized discount(203)(179)
Amounts due within one year(2)(1,502)
Total long-term debt due after one year$26,606 $24,151 
Credit Agreement
On April 7, 2026, MPLX entered into a new revolving credit facility (the “MPLX Credit Agreement”) to replace the previously existing credit facility, which was scheduled to expire July 2027. The MPLX Credit Agreement has a five-year term and expires in April 2031. MPLX’s total capacity under the MPLX Credit Agreement increased from $2.0 billion to $2.5 billion and includes sub-facilities for swing-line loans of up to $150 million and letters of credit of up to $150 million. 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 within ranges defined in the MPLX Credit Agreement, depending on MPLX’s credit ratings.
At September 30, 2026, MPLX had no outstanding borrowings and less than $1 million in letters of credit outstanding under this facility, resulting in total availability of approximately $2.5 billion or approximately 100 percent of the borrowing capacity.
Fixed Rate Senior Notes
MPLX’s senior notes, including those issued by consolidated subsidiaries, consist of various series of senior notes maturing between 2027 and 2058 with interest rates ranging from 2.650 percent to 6.200 percent. Interest on each series of notes is payable semi-annually in arrears on various dates depending on the series of the notes.
The following table summarizes debt issuances during the nine months ended September 30, 2026, all of which were issued in an underwritten public offering:
Issue DateAggregate
Principal Amount
(in millions)		Coupon (percent)Price to Public
(percent of par)		Interest Payment DatesMaturity Date
February 12, 2026$1,0005.30099.678April 1 and October 1April 1, 2036
February 12, 20265006.10098.453April 1 and October 1April 1, 2056
August 24, 20261,2504.70099.312May 1 and November 1November 1, 2029
August 24, 20265005.00098.972May 1 and November 1May 1, 2032
August 24, 20265005.50098.066May 1 and November 1November 1, 2036
In March 2026, MPLX used the proceeds from the issuance of senior notes in February 2026 to repay all of MPLX’s outstanding $1.5 billion aggregate principal amount of 1.750 percent senior notes at maturity.
In September 2026, MPLX used a portion of the proceeds from the issuance of senior notes in August 2026 to redeem the outstanding $1.25 billion aggregate principal amount of 4.125 percent senior notes due March 2027.
v3.26.3
Interest and Other Financial Costs
 9 Months Ended
Sep. 30, 2026
Other Income and Expenses [Abstract]  
Interest and Other Financial Costs Net Interest and Other Financial Costs
Net interest and other financial costs were as follows:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Interest expense$330 $279 $966 $767 
Other financial costs12 (9)32 14 
Interest income(12)(16)(42)(50)
Capitalized interest(30)(11)(76)(25)
Net interest and other financial costs$300 $243 $880 $706 
v3.26.3
Revenue
 9 Months Ended
Sep. 30, 2026
Revenue from Contract with Customer [Abstract]  
Revenue Revenue
Disaggregation of Revenue
The following tables represent a disaggregation of revenue for each reportable segment for the three and nine months ended September 30, 2026 and September 30, 2025:
Three Months Ended September 30, 2026
(In millions)
Crude Oil and Products Logistics
Natural Gas and NGL Services
Total
Revenues and other income:
Service revenue$94 $646 $740 
Service revenue - related parties1,178 7 1,185 
Service revenue - product related(1)
— 46 46 
Product sales(1)
1 668 669 
Product sales - related parties4 144 148 
Total revenues from contracts with customers$1,277 $1,511 2,788 
Non-ASC 606 revenue and other income(2)
817 
Total revenues and other income$3,605 
Three Months Ended September 30, 2025
(In millions)
Crude Oil and Products Logistics
Natural Gas and NGL Services
Total
Revenues and other income:
Service revenue$115 $635 $750 
Service revenue - related parties1,090 4 1,094 
Service revenue - product related— 64 64 
Product sales1 524 525 
Product sales - related parties3 23 26 
Total revenues from contracts with customers$1,209 $1,250 2,459 
Non-ASC 606 revenue and other income(2)
1,160 
Total revenues and other income$3,619 
Nine Months Ended September 30, 2026
(In millions)
Crude Oil and Products Logistics
Natural Gas and NGL Services
Total
Revenues and other income:
Service revenue$279 $1,875 $2,154 
Service revenue - related parties3,400 19 3,419 
Service revenue - product related(1)
— 135 135 
Product sales(1)
4 1,699 1,703 
Product sales - related parties12 329 341 
Total revenues from contracts with customers$3,695 $4,057 7,752 
Non-ASC 606 revenue and other income(2)
2,203 
Total revenues and other income$9,955 
Nine Months Ended September 30, 2025
(In millions)
Crude Oil and Products Logistics
Natural Gas and NGL Services
Total
Revenues and other income:
Service revenue$332 $1,821 $2,153 
Service revenue - related parties3,237 16 3,253 
Service revenue - product related— 233 233 
Product sales3 1,507 1,510 
Product sales - related parties9 117 126 
Total revenues from contracts with customers$3,581 $3,694 7,275 
Non-ASC 606 revenue and other income(2)
2,471 
Total revenues and other income$9,746 
(1)    Contains non-ASC 606 revenue from derivative-related activity as disclosed in Note 11.
(2)    Non-ASC 606 Revenue and other income includes rental income, sales-type lease revenue, income from equity method investments, and other income.
Contract Balances
The tables below reflect the changes in ASC 606 contract balances for the nine months ended September 30, 2026 and September 30, 2025:
(In millions)Balance at December 31, 2025Additions/ (Deletions)
Revenue Recognized(1)
Balance at September 30, 2026
Contract assets$15 $(14)$— $1 
Long-term contract assets4 — — 4 
Deferred revenue13 26 (19)20 
Deferred revenue - related parties66 63 (62)67 
Long-term deferred revenue117 (13)— 104 
Long-term deferred revenue - related parties45 3 — 48 
(In millions)Balance at December 31, 2024Additions/ (Deletions)
Revenue Recognized(1)
Balance at September 30, 2025
Contract assets$2 $10 $— $12 
Long-term contract assets— 4 — 4 
Deferred revenue84 22 (59)47 
Deferred revenue - related parties71 66 (62)75 
Long-term deferred revenue315 (15)— 300 
Long-term deferred revenue - related parties44 1 — 45 
(1)    No significant revenue was recognized related to past performance obligations in the periods presented.    
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 September 30, 2026. 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.
(In billions)
2026$0.5 
20272.0 
20280.8 
20290.5 
20300.4 
2031 and thereafter1.2 
Total estimated revenue on remaining performance obligations$5.4 
As of September 30, 2026, unsatisfied performance obligations included in the Consolidated Balance Sheets are $239 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.
v3.26.3
Leases
 9 Months Ended
Sep. 30, 2026
Leases [Abstract]  
Lessor, Sales-type Leases Leases
During the second quarter of 2026, a refining logistics agreement between MPLX and MPC was renewed which required reassessment of the agreement under ASC 842. As a result of the reassessment, the lease was reclassified from sales-type to operating. Accordingly, property, plant and equipment, net in the amount of $216 million was recognized by MPLX along with a reduction of lease receivable of $102 million and a reduction of unguaranteed residual asset of $100 million. There have been no other significant changes in our operating and sales-type lease obligations since those disclosed in the Annual Report on Form 10-K for the year ended December 31, 2025.

The following is a schedule of minimum future rental payments to be received on the non-cancellable operating leases as of September 30, 2026:
(In millions)Related PartyThird PartyTotal
2026$246 $24 $270 
2027935 84 1,019 
2028630 75 705 
2029473 73 546 
2030474 59 533 
2031 and thereafter763 185 948 
Total minimum future rentals$3,521 $500 $4,021 
Lessor, Operating Leases Leases
During the second quarter of 2026, a refining logistics agreement between MPLX and MPC was renewed which required reassessment of the agreement under ASC 842. As a result of the reassessment, the lease was reclassified from sales-type to operating. Accordingly, property, plant and equipment, net in the amount of $216 million was recognized by MPLX along with a reduction of lease receivable of $102 million and a reduction of unguaranteed residual asset of $100 million. There have been no other significant changes in our operating and sales-type lease obligations since those disclosed in the Annual Report on Form 10-K for the year ended December 31, 2025.

The following is a schedule of minimum future rental payments to be received on the non-cancellable operating leases as of September 30, 2026:
(In millions)Related PartyThird PartyTotal
2026$246 $24 $270 
2027935 84 1,019 
2028630 75 705 
2029473 73 546 
2030474 59 533 
2031 and thereafter763 185 948 
Total minimum future rentals$3,521 $500 $4,021 
v3.26.3
Supplemental Cash Flow Information
 9 Months Ended
Sep. 30, 2026
Supplemental Cash Flow Elements [Abstract]  
Supplemental Cash Flow Information Supplemental Cash Flow Information
Nine Months Ended 
September 30,
(In millions)20262025
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)$931 $705 
Income taxes paid4 3 
Cash paid for amounts included in the measurement of lease liabilities:
Payments on operating leases50 47 
Net cash provided by financing activities included:
Principal payments under finance lease obligations6 2 
Non-cash investing and financing activities:
Net transfers of property, plant and equipment to lease receivable187 123 
Contribution of assets(1)
— 115 
ROU assets obtained in exchange for new operating lease obligations10 30 
ROU assets obtained in exchange for new finance lease obligations4 3 
Book value of equity method investment(2)
— 282 
Contingent consideration(3)
— 234 
(1)    Represents the book value of assets contributed by MPLX to a joint venture.
(2)    Represents the book value of MPLX’s equity method investment in BANGL, prior to MPLX buying out the remaining interest in the entity. See Note 3 - BANGL, LLC Acquisition.
(3)    See Note 3 - BANGL, LLC Acquisition.
The Consolidated Statements of Cash Flows exclude changes to the Consolidated Balance Sheets that do not affect cash. The following is a reconciliation of additions to property, plant and equipment to total capital expenditures:
Nine Months Ended 
September 30,
(In millions)20262025
Additions to property, plant and equipment$2,195 $1,094 
Increase in capital accruals130 131 
Other— (22)
Total capital expenditures$2,325 $1,203 
v3.26.3
Commitments and Contingencies
 9 Months Ended
Sep. 30, 2026
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies Commitments and Contingencies
We are the subject of, or a party to, a number of pending or threatened legal actions, contingencies and commitments involving a variety of matters, including laws and regulations relating to the environment. Some of these matters are discussed below. For matters for which we have not recorded a liability, we are unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings, discovery or court proceedings. However, the ultimate resolution of some of these contingencies could, individually or in the aggregate, be material.
Environmental Matters
We are subject to federal, state 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.
Accrued liabilities for remediation totaled $17 million and $21 million at September 30, 2026 and December 31, 2025, respectively. It is not presently possible to estimate the ultimate amount of all remediation costs that might be incurred or the penalties, if any, that may be imposed.
We are involved in environmental enforcement matters arising in the ordinary course of business. While the outcome and impact on us cannot be predicted with certainty, management believes the resolution of these environmental matters will not, individually or collectively, have a material adverse effect on our consolidated results of operations, financial position or cash flows.
Other Legal Proceedings
Tesoro High Plains Pipeline
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. 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, 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 challenging the March 2021 order purporting to vacate all previous orders related to THPP’s alleged trespass. The case is proceeding on the merits of THPP’s challenge to the March 2021 order purporting to vacate all previous orders related to THPP’s alleged trespass.
We are also a party to a number of other lawsuits and other proceedings arising in the ordinary course of business. While the ultimate outcome and impact to us cannot be predicted with certainty, we believe the resolution of these other lawsuits and proceedings will not, individually or collectively, have a material adverse effect on our consolidated financial position, results of operations or cash flows.
Guarantees
Dakota Access Pipeline
We hold a 9.19 percent indirect interest in Dakota Access, which owns and operates the Bakken Pipeline system. We have entered into a Contingent Equity Contribution Agreement whereby we, along with the other joint venture owners in the Bakken Pipeline system, have agreed to make equity contributions to the joint venture upon vacatur of an easement that results in a shutdown of the pipeline to allow the entities that own and operate the Bakken Pipeline system to satisfy their senior note payment obligations. As of September 30, 2026, our maximum potential undiscounted payments under the Contingent Equity Contribution Agreement were approximately $78 million.
Contractual Commitments and Contingencies
From time to time and in the ordinary course of business, we and our affiliates provide guarantees of our subsidiaries’ payment and performance obligations in the Natural Gas and NGL Services segment. Certain natural gas processing and gathering arrangements require us 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 September 30, 2026, we do not believe there are any indications that we will not be able to meet the construction milestones, that force majeure does not apply or that such fees and charges will otherwise be triggered.
v3.26.3
Subsequent Events
 9 Months Ended
Sep. 30, 2026
Subsequent Events [Abstract]  
Subsequent Events Subsequent Event
Announced Divestiture of St. Paul Park and Mandan Logistics Assets
On November 2, 2026, we entered into a definitive agreement to divest our logistics assets associated with MPC’s St. Paul Park, Minnesota and Mandan, North Dakota refineries for $750 million in cash, subject to working capital and other closing adjustments. The carrying value of the associated net assets was $422 million as of September 30, 2026 and reported within the Crude Oil and Products Logistics segment. The transaction is expected to close in the fourth quarter of 2026, pending satisfaction of customary closing conditions and regulatory approvals.
v3.26.3
Insider Trading Arrangements
 3 Months Ended
Sep. 30, 2026
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement
During the quarter ended September 30, 2026, 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
v3.26.3
Description of the Business and Basis of Presentation Accounting Policies (Policies)
 9 Months Ended
Mar. 27, 2012
Sep. 30, 2026
Accounting Policies [Abstract]    
Nature of Operations   We are engaged in the gathering, transportation, storage and distribution of crude oil, refined products, other hydrocarbon-based products and renewables; the gathering, treating, 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.
Refer to Note 8 for additional information about our operations.
Limited Liability Company or Limited Partnership, Business, Formation Date Mar. 27, 2012  
Basis of Accounting, Policy  
These interim consolidated financial statements are unaudited; however, in the opinion of MPLX’s management, these statements reflect all adjustments necessary for a fair statement of the results for the periods reported. All such adjustments are of a normal, recurring nature unless otherwise disclosed. These interim consolidated financial statements, including the notes, have been prepared in accordance with the rules and regulations of the SEC applicable to interim period financial statements and do not include all of the information and disclosures required by GAAP for complete financial statements. Certain information derived from our audited annual financial statements, prepared in accordance with GAAP, has been condensed or omitted from these interim financial statements.
Consolidation, Policy  
MPLX’s 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.
v3.26.3
Net Income Per Limited Partner Unit Accounting Policy (Policies)
 9 Months Ended
Sep. 30, 2026
Accounting Policies [Abstract]  
Earnings Per Unit, Policy
Net income per unit applicable to common 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.
v3.26.3
Acquisitions and Other Transactions (Tables)
 9 Months Ended
Sep. 30, 2026
Northwind Midstream  
Business Combination [Line Items]  
Business Combination, Recognized Asset Acquired and Liability Assumed The following table reflects our allocation of the $2.4 billion purchase price to the Northwind Midstream assets and liabilities, as well as measurement period adjustments since the acquisition date:
(In millions)August 29,
2025		AdjustmentsAs adjusted
Assets acquired:
Cash and cash equivalents$17 $— $17 
Receivables11 — 11 
Other current assets1 — 1 
Property, plant and equipment1,182 (15)1,167 
Intangibles951 6 957 
Other noncurrent assets2 — 2 
Total assets acquired2,164 (9)2,155 
Liabilities assumed:
Accounts payable15 7 22 
Accrued property, plant and equipment84 (2)82 
Accrued liabilities6 4 10 
Other current liabilities1 — 1 
Long-term operating lease liabilities1 — 1 
Total liabilities assumed107 9 116 
Total identifiable net assets2,057 (18)2,039 
Goodwill356 4 360 
Fair value of net assets acquired$2,413 $(14)$2,399 
BANGL, LLC  
Business Combination [Line Items]  
Business Combination, Recognized Asset Acquired and Liability Assumed The following table reflects our determination of the fair value of the BANGL assets and liabilities:
(In millions)July 1,
2025
Assets acquired:
Cash and cash equivalents$18 
Other current assets4 
Property, plant and equipment1,550 
Intangibles77 
Other noncurrent assets22 
Total assets acquired1,671 
Liabilities assumed:
Long-term debt due within one year46 
Other current liabilities42 
Long-term debt610 
Other long-term liabilities1 
Total liabilities assumed699 
Total identifiable net assets972 
Goodwill731 
Fair value of net assets acquired$1,703 
Schedule of Business Combination, Consideration
The following table summarizes the purchase price consideration in connection with the BANGL Acquisition:
Total cash paid$703 
Fair value of contingent consideration as of acquisition date234 
Total consideration937 
Fair value of previously held equity interest766 
Fair value of net assets acquired$1,703 
v3.26.3
Investments and Noncontrolling Interests (Tables)
 9 Months Ended
Sep. 30, 2026
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 ofCarrying value at
September 30,September 30,December 31,
(In millions, except ownership percentages)VIE202620262025
Crude Oil and Products Logistics
Illinois Extension Pipeline Company, L.L.C.35%$214 $208 
LOOP LLC41%309 313 
MarEn Bakken Company LLC(1)
25%486 502 
Other(2)
X
17 - 67%
542 558 
Total Crude Oil and Products Logistics
1,551 1,581 
Natural Gas and NGL Services
Eiger Express Holdings, LLCX15%199 34 
MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C.X67%393 407 
MarkWest Utica EMG, L.L.C.X62%992 890 
MXP Parent, LLC10%269 198 
Ohio Gathering Company L.L.C.(3)
X31%426 444 
Sherwood Midstream LLCX50%464 475 
Texas City Logistics LLCX50%409 163 
WPC Parent, LLC30%320 273 
Other(2)
X
10 - 51%
423 333 
Total Natural Gas and NGL Services
3,895 3,217 
Total$5,446 $4,798 
(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, the “Bakken Pipeline system”).
(2)    Included within Other are certain equity method investments that have been deemed to be VIEs.
(3)    MPLX also holds a 43 percent indirect interest in Ohio Gathering Company L.L.C. through our ownership interest in MarkWest Utica EMG, L.L.C.
v3.26.3
Related Party Agreements and Transactions (Tables)
 9 Months Ended
Sep. 30, 2026
Related Party Transactions [Abstract]  
Schedule of Related Party Transactions
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 and deferred revenue.
(In millions)September 30,
2026		December 31,
2025
Current assets - related parties
Receivables$814 $624 
Lease receivables228 269 
Prepaid13 5 
Other1 1 
Total1,056 899 
Noncurrent assets - related parties
Long-term lease receivables243 421 
Right of use assets238 239 
Unguaranteed residual assets243 263 
Long-term receivables46 39 
Total770 962 
Current liabilities - related parties
MPC Loan Agreement and other payables(1)
346 290 
Derivative liabilities25 — 
Deferred revenue101 107 
Operating lease liabilities2 2 
Total474 399 
Long-term liabilities - related parties
Long-term operating lease liabilities235 237 
Long-term deferred revenue180 127 
Total$415 $364 
(1)    There were no borrowings outstanding on the MPC Loan Agreement as of September 30, 2026 or December 31, 2025.
v3.26.3
Equity (Tables)
 9 Months Ended
Sep. 30, 2026
Equity [Abstract]  
Schedule of Stockholders Equity
The changes in the number of common units during the nine months ended September 30, 2026 are summarized below:
(In units)Common Units
Balance at December 31, 20251,015,702,040 
Unit-based compensation awards134,291 
Units redeemed in unit repurchase program(2,627,468)
Balance at September 30, 20261,013,208,863 
Class of Treasury Stock Total unit repurchases were as follows for the respective periods:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions, except per unit data)2026202520262025
Number of common units repurchased1 2 3 6 
Cash paid for common units repurchased(1)
$50 $100 $150 $300 
Average cost per unit(1)
$58.69 $50.86 $57.09 $51.20 
(1)    Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.
Dividends Declared
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions, except per unit data)2026202520262025
Distribution declared:
Limited partner units - public$442 $397 $1,232 $1,110 
Limited partner units - MPC784 698 2,178 1,936 
Total distribution declared$1,226 $1,095 $3,410 $3,046 
Quarterly cash distributions declared per limited partner common unit$1.2111 $1.0765 $3.3641 $2.9895 
v3.26.3
Net Income Per Limited Partner Unit (Tables)
 9 Months Ended
Sep. 30, 2026
Earnings Per Share [Abstract]  
Schedule of Net Income Per Unit, Basic and Diluted
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions, except per unit data)2026202520262025
Net income attributable to MPLX LP(1):
$1,164 $1,545 $3,153 $3,719 
Less: Distributed and undistributed earnings allocated to other participating securities1 1 2 2 
Net income available to common unitholders$1,163 $1,544 $3,151 $3,717 
Weighted average units outstanding:
Basic1,014 1,019 1,014 1,020 
Diluted1,014 1,019 1,015 1,020 
Net income attributable to MPLX LP per limited partner unit:
Basic$1.15 $1.52 $3.11 $3.65 
Diluted$1.15 $1.52 $3.11 $3.65 
(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.
v3.26.3
Segment Information (Tables)
 9 Months Ended
Sep. 30, 2026
Segment Reporting [Abstract]  
Segment Reporting
The tables below present information about our reportable segments:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Crude Oil and Products Logistics
Service revenue$1,272 $1,205 $3,679 $3,569 
Rental income298 239 829 682 
Product related revenue5 4 16 12 
Sales-type lease revenue77 113 264 344 
Income from equity method investments83 71 197 186 
Other income33 28 91 94 
Total segment revenues and other income(1)
1,768 1,660 5,076 4,887 
Operating expenses582 553 1,686 1,613 
Other segment items(2)
(18)(30)(86)(98)
Segment Adjusted EBITDA(3)
1,204 1,137 3,476 3,372 
Capital expenditures174 147 409 391 
Investments in unconsolidated affiliates(4)
— 13 — 13 
Natural Gas and NGL Services
Service revenue653 639 1,894 1,837 
Rental income58 57 176 169 
Product related revenue858 611 2,163 1,857 
Sales-type lease revenue 51 37 139 110 
Income from equity method investments199 115 447 356 
Gain on equity method investments(5)
— 484 — 484 
Other income18 16 60 46 
Total segment revenues and other income(1)
1,837 1,959 4,879 4,859 
Purchased product costs734 493 1,819 1,384 
Operating expenses435 426 1,281 1,293 
Other segment items(2)
13 411 (108)341 
Segment Adjusted EBITDA(3)
655 629 1,887 1,841 
Capital expenditures667 447 1,916 812 
Investments in unconsolidated affiliates(4)
$281 $227 $720 $549 
(1)    Within the total segment revenues and other income amounts presented above, third-party revenues for the Crude Oil and Products Logistics segment were $189 million and $508 million for the three and nine months ended September 30, 2026, respectively, and $201 million and $565 million for the three and nine months ended September 30, 2025, respectively. Third-party revenues for the Natural Gas and NGL Services segment were $1,669 million and $4,482 million for the three and nine months ended September 30, 2026, respectively, and $1,917 million and $4,682 million for the three and nine months ended September 30, 2025, 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, 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 three and nine months ended September 30, 2026 and September 30, 2025 include cash contributions to several joint ventures to fund current growth capital projects. Investments in unconsolidated affiliates for the nine months ended September 30, 2025 exclude $151 million related to the acquisition of an additional interest in the joint venture that owns and operates the Matterhorn Express Pipeline, and the three and nine months ended September 30, 2025 exclude a $49 million capital contribution to WPC Parent, LLC to purchase Enbridge’s special membership interest in the Bay Runner Pipeline project and a $13 million payment related to earnout associated with MXP Parent, LLC.
(5)    The three and nine months ended September 30, 2025 represent the gain on remeasurement of our existing equity investment in BANGL in conjunction with the BANGL Acquisition.
Reconciliation of Other Significant Reconciling Items from Segments to Consolidated
The table below provides a reconciliation of Segment Adjusted EBITDA for reportable segments to Net income.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Reconciliation to Net income:
Crude Oil and Products Logistics Segment Adjusted EBITDA
$1,204 $1,137 $3,476 $3,372 
Natural Gas and NGL Services Segment Adjusted EBITDA
655 629 1,887 1,841 
Total reportable segments1,859 1,766 5,363 5,213 
Depreciation and amortization(1)
(378)(346)(1,101)(996)
Gain on equity method investments— 484 — 484 
Net interest and other financial costs(300)(243)(880)(706)
Income from equity method investments282 186 644 542 
Distributions/adjustments related to equity method investments(250)(251)(735)(707)
Transaction-related costs(2)
— (21)— (21)
Adjusted EBITDA attributable to noncontrolling interests11 11 33 33 
Other(3)
(50)(31)(141)(93)
Net income$1,174 $1,555 $3,183 $3,749 
(1)    Depreciation and amortization attributable to Crude Oil and Products Logistics was $154 million and $443 million for the three and nine months ended September 30, 2026, respectively, and $139 million and $407 million for the three and nine months ended September 30, 2025, respectively. Depreciation and amortization attributable to Natural Gas and NGL Services was $224 million and $658 million for the three and nine months ended September 30, 2026, respectively, and $207 million and $589 million for the three and nine months ended September 30, 2025, respectively.
(2)    Transaction-related costs include costs associated with acquisition and divestiture-related activities, including significant transactions discussed in Note 3.
(3)    Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.
v3.26.3
Property, Plant and Equipment (Tables)
 9 Months Ended
Sep. 30, 2026
Property, Plant, and Equipment [Abstract]  
Summary of Property, Plant and Equipment
Property, plant and equipment with associated accumulated depreciation is shown below:
September 30, 2026December 31, 2025
(In millions)Gross PP&EAccumulated DepreciationNet PP&EGross PP&EAccumulated DepreciationNet PP&E
Crude Oil and Products Logistics
$14,369 $5,452 $8,917 $13,809 $5,058 $8,751 
Natural Gas and NGL Services
19,696 5,531 14,165 17,950 5,003 12,947 
Total$34,065 $10,983 $23,082 $31,759 $10,061 $21,698 
v3.26.3
Fair Value Measurements (Tables)
 9 Months Ended
Sep. 30, 2026
Fair Value Disclosures [Abstract]  
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis
The following table presents the impact on the Consolidated Balance Sheets of MPLX’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2026 and December 31, 2025 by fair value hierarchy level.
September 30, 2026December 31, 2025
(In millions)Level 1Level 2Level 3Level 1Level 2Level 3
Liabilities:
Embedded derivatives in commodity contracts
Other current liabilities$— $— $13 $— $— $6 
Other long-term liabilities— — 40 — — 35 
Total embedded derivatives in commodity contracts— — 53 — — 41 
Contingent consideration / Other long-term liabilities— — 238 — — 236 
Commodity contracts - related party— 25 — — — — 
Total carrying value in Consolidated Balance Sheets$— $25 $291 $— $— $277 
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation
The following table is a reconciliation of the net beginning and ending balances recorded for net liabilities classified as Level 3 in the fair value hierarchy.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Beginning balance$(282)$(55)$(277)$(58)
Contingent consideration(1)
— (234)— (234)
Unrealized and realized gain/(loss) included in Net income(2)
(13)2 (23)(1)
Settlements4 2 9 8 
Ending balance$(291)$(285)$(291)$(285)
The amount of total gain/(loss) for the period included in earnings attributable to the change in unrealized gain/(loss) relating to liabilities still held at end of period$(12)$2 $(19)$(1)
(1)    Liability recorded in the third quarter of 2025 related to the BANGL Acquisition earnout provision.
(2)    Gain/(loss) on derivatives embedded in commodity contracts are recorded in Purchased product costs in the Consolidated Statements of Income.
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:
September 30, 2026December 31, 2025
(In millions)Fair ValueCarrying ValueFair ValueCarrying Value
Outstanding debt(1)
$24,381 $26,797 $24,887 $25,821 
(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.
v3.26.3
Derivative Financial Instruments (Tables)
 9 Months Ended
Sep. 30, 2026
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value
The following table presents the fair value of derivative instruments as of September 30, 2026 and December 31, 2025, and the line items in the Consolidated Balance Sheets in which the fair values are reflected. As of September 30, 2026 and December 31, 2025, there were no derivative assets or liabilities that were offset in the Consolidated Balance Sheets.
(In millions)September 30, 2026December 31, 2025
Commodity derivatives
Current liabilities - related parties$25 $— 
Other current liabilities(1)
13 6 
Other long-term liabilities(1)
40 35 
(1)    Includes embedded derivatives.
Schedule of Derivative Instruments, Gain (Loss)
The impact of MPLX’s derivative contracts not designated as hedging instruments and the location of gains and losses recognized in the Consolidated Statements of Income is summarized below:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Product sales
Realized loss$(2)$— $(6)$— 
Unrealized loss(2)— (4)— 
Product sales loss(4)— (10)— 
Service revenue - product related
Realized loss(16)— (37)— 
Unrealized loss(9)— (21)— 
Service revenue - product related loss(25)— (58)— 
Purchased product costs
Realized loss(3)(2)(8)(8)
Unrealized gain/(loss)(7)4 (13)7 
Purchased product costs gain/(loss)(10)2 (21)(1)
Total derivative gain/(loss) included in Net income$(39)$2 $(89)$(1)
v3.26.3
Debt (Tables)
 9 Months Ended
Sep. 30, 2026
Debt Disclosure [Abstract]  
Schedule of Debt
MPLX’s outstanding borrowings consist of the following:
(In millions)September 30,
2026		December 31,
2025
MPLX LP:
Fixed rate senior notes$26,969 $25,969 
Consolidated subsidiaries:
ANDX31 31 
Finance lease obligations5 6 
Total27,005 26,006 
Unamortized debt issuance costs(194)(174)
Unamortized discount(203)(179)
Amounts due within one year(2)(1,502)
Total long-term debt due after one year$26,606 $24,151 
Schedule of Long-Term Debt Instruments
The following table summarizes debt issuances during the nine months ended September 30, 2026, all of which were issued in an underwritten public offering:
Issue DateAggregate
Principal Amount
(in millions)		Coupon (percent)Price to Public
(percent of par)		Interest Payment DatesMaturity Date
February 12, 2026$1,0005.30099.678April 1 and October 1April 1, 2036
February 12, 20265006.10098.453April 1 and October 1April 1, 2056
August 24, 20261,2504.70099.312May 1 and November 1November 1, 2029
August 24, 20265005.00098.972May 1 and November 1May 1, 2032
August 24, 20265005.50098.066May 1 and November 1November 1, 2036
v3.26.3
Interest and Other Financial Costs (Tables)
 9 Months Ended
Sep. 30, 2026
Other Income and Expenses [Abstract]  
Interest and Other Financial Costs
Net interest and other financial costs were as follows:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2026202520262025
Interest expense$330 $279 $966 $767 
Other financial costs12 (9)32 14 
Interest income(12)(16)(42)(50)
Capitalized interest(30)(11)(76)(25)
Net interest and other financial costs$300 $243 $880 $706 
v3.26.3
Revenue (Tables)
 9 Months Ended
Sep. 30, 2026
Revenue from Contract with Customer [Abstract]  
Disaggregation of Revenue Table
The following tables represent a disaggregation of revenue for each reportable segment for the three and nine months ended September 30, 2026 and September 30, 2025:
Three Months Ended September 30, 2026
(In millions)
Crude Oil and Products Logistics
Natural Gas and NGL Services
Total
Revenues and other income:
Service revenue$94 $646 $740 
Service revenue - related parties1,178 7 1,185 
Service revenue - product related(1)
— 46 46 
Product sales(1)
1 668 669 
Product sales - related parties4 144 148 
Total revenues from contracts with customers$1,277 $1,511 2,788 
Non-ASC 606 revenue and other income(2)
817 
Total revenues and other income$3,605 
Three Months Ended September 30, 2025
(In millions)
Crude Oil and Products Logistics
Natural Gas and NGL Services
Total
Revenues and other income:
Service revenue$115 $635 $750 
Service revenue - related parties1,090 4 1,094 
Service revenue - product related— 64 64 
Product sales1 524 525 
Product sales - related parties3 23 26 
Total revenues from contracts with customers$1,209 $1,250 2,459 
Non-ASC 606 revenue and other income(2)
1,160 
Total revenues and other income$3,619 
Nine Months Ended September 30, 2026
(In millions)
Crude Oil and Products Logistics
Natural Gas and NGL Services
Total
Revenues and other income:
Service revenue$279 $1,875 $2,154 
Service revenue - related parties3,400 19 3,419 
Service revenue - product related(1)
— 135 135 
Product sales(1)
4 1,699 1,703 
Product sales - related parties12 329 341 
Total revenues from contracts with customers$3,695 $4,057 7,752 
Non-ASC 606 revenue and other income(2)
2,203 
Total revenues and other income$9,955 
Nine Months Ended September 30, 2025
(In millions)
Crude Oil and Products Logistics
Natural Gas and NGL Services
Total
Revenues and other income:
Service revenue$332 $1,821 $2,153 
Service revenue - related parties3,237 16 3,253 
Service revenue - product related— 233 233 
Product sales3 1,507 1,510 
Product sales - related parties9 117 126 
Total revenues from contracts with customers$3,581 $3,694 7,275 
Non-ASC 606 revenue and other income(2)
2,471 
Total revenues and other income$9,746 
(1)    Contains non-ASC 606 revenue from derivative-related activity as disclosed in Note 11.
(2)    Non-ASC 606 Revenue and other income includes rental income, sales-type lease revenue, income from equity method investments, and other income.
Schedule of Contract with Customer, Contract Asset, Contract Liability, and Receivable
The tables below reflect the changes in ASC 606 contract balances for the nine months ended September 30, 2026 and September 30, 2025:
(In millions)Balance at December 31, 2025Additions/ (Deletions)
Revenue Recognized(1)
Balance at September 30, 2026
Contract assets$15 $(14)$— $1 
Long-term contract assets4 — — 4 
Deferred revenue13 26 (19)20 
Deferred revenue - related parties66 63 (62)67 
Long-term deferred revenue117 (13)— 104 
Long-term deferred revenue - related parties45 3 — 48 
(In millions)Balance at December 31, 2024Additions/ (Deletions)
Revenue Recognized(1)
Balance at September 30, 2025
Contract assets$2 $10 $— $12 
Long-term contract assets— 4 — 4 
Deferred revenue84 22 (59)47 
Deferred revenue - related parties71 66 (62)75 
Long-term deferred revenue315 (15)— 300 
Long-term deferred revenue - related parties44 1 — 45 
(1)    No significant revenue was recognized related to past performance obligations in the periods presented.
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
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 September 30, 2026. 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.
(In billions)
2026$0.5 
20272.0 
20280.8 
20290.5 
20300.4 
2031 and thereafter1.2 
Total estimated revenue on remaining performance obligations$5.4 
As of September 30, 2026, unsatisfied performance obligations included in the Consolidated Balance Sheets are $239 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.
v3.26.3
Leases (Tables)
 9 Months Ended
Sep. 30, 2026
Leases [Abstract]  
Lessor, Operating Lease, Payment to be Received, Maturity
The following is a schedule of minimum future rental payments to be received on the non-cancellable operating leases as of September 30, 2026:
(In millions)Related PartyThird PartyTotal
2026$246 $24 $270 
2027935 84 1,019 
2028630 75 705 
2029473 73 546 
2030474 59 533 
2031 and thereafter763 185 948 
Total minimum future rentals$3,521 $500 $4,021 
v3.26.3
Supplemental Cash Flow Information (Tables)
 9 Months Ended
Sep. 30, 2026
Supplemental Cash Flow Elements [Abstract]  
Schedule of Cash Flow, Supplemental Disclosures
Nine Months Ended 
September 30,
(In millions)20262025
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)$931 $705 
Income taxes paid4 3 
Cash paid for amounts included in the measurement of lease liabilities:
Payments on operating leases50 47 
Net cash provided by financing activities included:
Principal payments under finance lease obligations6 2 
Non-cash investing and financing activities:
Net transfers of property, plant and equipment to lease receivable187 123 
Contribution of assets(1)
— 115 
ROU assets obtained in exchange for new operating lease obligations10 30 
ROU assets obtained in exchange for new finance lease obligations4 3 
Book value of equity method investment(2)
— 282 
Contingent consideration(3)
— 234 
(1)    Represents the book value of assets contributed by MPLX to a joint venture.
(2)    Represents the book value of MPLX’s equity method investment in BANGL, prior to MPLX buying out the remaining interest in the entity. See Note 3 - BANGL, LLC Acquisition.
(3)    See Note 3 - BANGL, LLC Acquisition.
Summary of Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures
The Consolidated Statements of Cash Flows exclude changes to the Consolidated Balance Sheets that do not affect cash. The following is a reconciliation of additions to property, plant and equipment to total capital expenditures:
Nine Months Ended 
September 30,
(In millions)20262025
Additions to property, plant and equipment$2,195 $1,094 
Increase in capital accruals130 131 
Other— (22)
Total capital expenditures$2,325 $1,203 
v3.26.3
Acquisitions and Other Transactions (Northwind Midstream) (Details) - USD ($)
$ in Millions
Aug. 29, 2025
Sep. 30, 2026
Dec. 31, 2025
Aug. 11, 2025
Business Combination [Line Items]        
Goodwill   $ 8,736 $ 8,755  
Senior Notes [Member]        
Business Combination [Line Items]        
Debt Instrument, Face Amount       $ 4,500
Northwind Midstream        
Business Combination [Line Items]        
Business Combination, Voting Equity Interest Acquired, Percentage 100.00%      
Payments to Acquire Businesses, Gross $ 2,400      
Intangible Asset, Finite-Lived, Acquired, Weighted-Average Amortization Period 15 years      
Goodwill $ 360      
v3.26.3
Acquisitions and Other Transactions (Northwind Midstream - Assets Acquired and Liabilities Assumed) (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Aug. 29, 2025
Business Combination, Recognized Liability Assumed, Liability [Abstract]      
Goodwill $ 8,736 $ 8,755  
Northwind Midstream      
Business Combination, Recognized Asset Acquired, Asset [Abstract]      
Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent     $ 17
Business Combination, Recognized Asset Acquired, Receivable, Current     11
Other current assets     1
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment     1,167
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill     957
Business Combination, Recognized Asset Acquired, Other Asset, Noncurrent     2
Business Combination, Recognized Asset Acquired, Asset     2,155
Business Combination, Recognized Liability Assumed, Liability [Abstract]      
Business Combination, Recognized Liability Assumed, Accounts Payable, Current     22
Business Combination, Recognized Liability Assumed, Accrued Property, Plant and Equipment, Current     82
Business Combination, Recognized Liability Assumed, Accrued Liabilities, Current     10
Other current liabilities     1
Long-term operating lease liabilities     1
Business Combination, Recognized Liability Assumed, Liability     116
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)     2,039
Goodwill     360
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill     2,399
Northwind Midstream | Previously Reported      
Business Combination, Recognized Asset Acquired, Asset [Abstract]      
Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent     17
Business Combination, Recognized Asset Acquired, Receivable, Current     11
Other current assets     1
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment     1,182
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill     951
Business Combination, Recognized Asset Acquired, Other Asset, Noncurrent     2
Business Combination, Recognized Asset Acquired, Asset     2,164
Business Combination, Recognized Liability Assumed, Liability [Abstract]      
Business Combination, Recognized Liability Assumed, Accounts Payable, Current     15
Business Combination, Recognized Liability Assumed, Accrued Property, Plant and Equipment, Current     84
Business Combination, Recognized Liability Assumed, Accrued Liabilities, Current     6
Other current liabilities     1
Long-term operating lease liabilities     1
Business Combination, Recognized Liability Assumed, Liability     107
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)     2,057
Goodwill     356
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill     2,413
Northwind Midstream | Revision of Prior Period, Adjustment      
Business Combination, Recognized Asset Acquired, Asset [Abstract]      
Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent     0
Business Combination, Recognized Asset Acquired, Receivable, Current     0
Other current assets     0
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment     (15)
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill     6
Business Combination, Recognized Asset Acquired, Other Asset, Noncurrent     0
Business Combination, Recognized Asset Acquired, Asset     (9)
Business Combination, Recognized Liability Assumed, Liability [Abstract]      
Business Combination, Recognized Liability Assumed, Accounts Payable, Current     7
Business Combination, Recognized Liability Assumed, Accrued Property, Plant and Equipment, Current     (2)
Business Combination, Recognized Liability Assumed, Accrued Liabilities, Current     4
Other current liabilities     0
Long-term operating lease liabilities     0
Business Combination, Recognized Liability Assumed, Liability     9
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)     (18)
Goodwill     4
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill     $ (14)
v3.26.3
Acquisitions and Other Transactions (Divestiture of Rockies Operations) (Details)
$ in Millions
Nov. 12, 2025
USD ($)
Rockies Operations | Disposal Group, Not Discontinued Operations  
Disposal Group, Including Discontinued Operations [Line Items]  
Disposal Group, Including Discontinued Operation, Consideration $ 980
v3.26.3
Acquisitions and Other Transactions (BANGL, LLC Acquisitions) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jul. 03, 2025
Jul. 01, 2025
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Business Combination [Line Items]              
Gain on equity method investments     $ 0 $ 484 $ 0 $ 484  
Goodwill     $ 8,736   $ 8,736   $ 8,755
BANGL, LLC              
Business Combination [Line Items]              
Equity Method Investment, Remaining Ownership Interest Purchased   55.00%          
Payments to Acquire Businesses, Gross   $ 703          
Business Combination, Contingent Consideration, Range of Outcomes, Maximum, Amount   275          
Repayments of Debt $ 656            
Gain on equity method investments   $ 484          
Business Combination, Voting Equity Interest Acquired, Percentage   100.00%          
Intangible Asset, Finite-Lived, Acquired, Weighted-Average Amortization Period   11 years          
Goodwill   $ 731          
Business Combination Purchase Price Allocation Goodwill Expected Tax Deductible Percent   55.00%          
BANGL, LLC | Maximum [Member]              
Business Combination [Line Items]              
Alternative Investment, Measurement Input   0.12          
Alternative Investment, Valuation Technique [Extensible Enumeration]   Valuation Technique, Discounted Cash Flow [Member]          
BANGL, LLC | Minimum [Member]              
Business Combination [Line Items]              
Alternative Investment, Measurement Input   0.11          
Alternative Investment, Valuation Technique [Extensible Enumeration]   Valuation Technique, Discounted Cash Flow [Member]          
BANGL, LLC | Natural Gas and NGL Services              
Business Combination [Line Items]              
Goodwill   $ 731          
v3.26.3
Acquisitions and Other Transactions (BANGL, LLC Acquisitions - Total Consideration) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jul. 01, 2025
Sep. 30, 2026
Sep. 30, 2025
 [1]
Sep. 30, 2026
Sep. 30, 2025
 [1],[2]
Business Combination [Line Items]          
Contingent consideration(3)   $ 0 $ 234 $ 0 $ 234
BANGL, LLC          
Business Combination [Line Items]          
Payments to Acquire Businesses, Gross $ 703        
Contingent consideration(3) 234        
Business Combination, Voting Equity Interest Acquired, Percentage 937        
Repayments of Debt 766        
Business Combination, Consideration Transferred and Preacquisition Equity Interest in Acquiree $ 1,703        
[1] Liability recorded in the third quarter of 2025 related to the BANGL Acquisition earnout provision.
[2] See Note 3 - BANGL, LLC Acquisition.
v3.26.3
Acquisitions and Other Transactions (BANGL, LLC Acquisitions - Assets and Liabilities Purchased) (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Jul. 01, 2025
Business Combination [Line Items]      
Goodwill $ 8,736 $ 8,755  
BANGL, LLC      
Business Combination [Line Items]      
Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent     $ 18
Other current assets     4
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment     1,550
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill     77
Other noncurrent assets     22
Business Combination, Recognized Asset Acquired, Asset     1,671
Long-Term Debt, Maturity, Year One     46
Other current liabilities     42
Long-Term Debt     610
Liabilities, Other than Long-Term Debt, Noncurrent     1
Business Combination, Recognized Liability Assumed, Liability     699
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less)     972
Goodwill     731
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill     $ 1,703
v3.26.3
Acquisitions and Other Transactions (Matterhorn) (Details) - USD ($)
$ in Millions
 9 Months Ended
Jun. 16, 2025
Sep. 30, 2026
Sep. 30, 2025
Business Combination [Line Items]      
Investments - acquisitions and contributions   $ 720 $ 776
MXP Parent, LLC      
Business Combination [Line Items]      
Equity Method Investment, Addition Ownership Acquired 5.00%    
Equity method investment, ownership percentage 10.00%    
Difference between carrying amount and underlying equity $ 124    
MXP Parent, LLC | Natural Gas and NGL Services      
Business Combination [Line Items]      
Investments - acquisitions and contributions 151    
Equity method investment, ownership percentage   10.00%  
MXP Parent, LLC | Property, Plant and Equipment      
Business Combination [Line Items]      
Difference between carrying amount and underlying equity 63    
MXP Parent, LLC | Customer-Related Intangible Assets      
Business Combination [Line Items]      
Difference between carrying amount and underlying equity $ 61    
v3.26.3
Acquisitions and Other Transactions (Whiptail Midstream) (Details) - USD ($)
$ in Millions
 9 Months Ended
Mar. 11, 2025
Sep. 30, 2026
Sep. 30, 2025
Business Combination [Line Items]      
Acquisitions, net of cash acquired   $ (14) $ 3,316
Whiptail Midstream Acquisition      
Business Combination [Line Items]      
Acquisitions, net of cash acquired $ 235    
Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment 170    
Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Excluding Goodwill 41    
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Net Working Capital $ 24    
v3.26.3
Investments and Noncontrolling Interests (Schedule of Equity Method Investments) (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Jun. 16, 2025
Schedule of Equity Method Investments      
Equity method investments $ 5,446 $ 4,798  
MXP Parent, LLC      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage     10.00%
Crude Oil and Products Logistics      
Schedule of Equity Method Investments      
Equity method investments $ 1,551 1,581  
Crude Oil and Products Logistics | Illinois Extension Pipeline Company, L.L.C.      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 35.00%    
Equity method investments $ 214 208  
Crude Oil and Products Logistics | LOOP LLC      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 41.00%    
Equity method investments $ 309 313  
Crude Oil and Products Logistics | MarEn Bakken Company LLC(1)      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 25.00%    
Equity method investments [1] $ 486 502  
Crude Oil and Products Logistics | Other(2)      
Schedule of Equity Method Investments      
Equity method investments [2] $ 542 558  
Crude Oil and Products Logistics | Other(2) | Minimum [Member]      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 17.00%    
Crude Oil and Products Logistics | Other(2) | Maximum [Member]      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 67.00%    
Crude Oil and Products Logistics | Indirect Ownership Interest [Member] | Bakken Pipeline System [Member]      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 9.19%    
Natural Gas and NGL Services      
Schedule of Equity Method Investments      
Equity method investments $ 3,895 3,217  
Natural Gas and NGL Services | Other(2)      
Schedule of Equity Method Investments      
Equity method investments [2] $ 423 333  
Natural Gas and NGL Services | Other(2) | Minimum [Member]      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 10.00%    
Natural Gas and NGL Services | Other(2) | Maximum [Member]      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 51.00%    
Natural Gas and NGL Services | Eiger Express Holdings, LLC      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 15.00%    
Equity method investments $ 199 34  
Natural Gas and NGL Services | MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C.      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 67.00%    
Equity method investments $ 393 407  
Natural Gas and NGL Services | MarkWest Utica EMG, L.L.C.      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 62.00%    
Equity method investments $ 992 890  
Natural Gas and NGL Services | MXP Parent, LLC      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 10.00%    
Equity method investments $ 269 198  
Natural Gas and NGL Services | Ohio Gathering Company L.L.C.      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 31.00%    
Equity method investments [3] $ 426 444  
Natural Gas and NGL Services | Sherwood Midstream LLC      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 50.00%    
Equity method investments $ 464 475  
Natural Gas and NGL Services | Texas City Logistics LLC      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 50.00%    
Equity method investments $ 409 163  
Natural Gas and NGL Services | WPC Parent, LLC      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 30.00%    
Equity method investments $ 320 $ 273  
Natural Gas and NGL Services | Indirect Ownership Interest [Member] | Ohio Gathering Company L.L.C.      
Schedule of Equity Method Investments      
Equity method investment, ownership percentage 43.00%    
[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, the “Bakken Pipeline system”).
[2] Included within Other are certain equity method investments that have been deemed to be VIEs.
[3] MPLX also holds a 43 percent indirect interest in Ohio Gathering Company L.L.C. through our ownership interest in MarkWest Utica EMG, L.L.C.
v3.26.3
Related Party Loan (Details) - Revolving Credit Facility - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Oct. 30, 2026
Dec. 31, 2025
Related Party Transaction [Line Items]        
Related party debt borrowings $ 231 $ 50    
Repayments of Related Party Debt 231 $ 50    
Related Party [Member]        
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 plus 1.25 percent      
Line of Credit Facility, Interest Rate During Period 4.90% 5.68%    
Line of Credit, Current $ 0 $ 0   $ 0
Related Party [Member] | Subsequent Event        
Related Party Transaction [Line Items]        
Line of Credit Facility, Current Borrowing Capacity     $ 2,500  
v3.26.3
Related Party Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Related Party [Member]        
Related Party Transaction [Line Items]        
Sales Revenue, Goods, Related Party, Net Zero $ 436 $ 151 $ 993 $ 476
v3.26.3
Related Party Expenses (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Related Party Transaction [Line Items]        
General and administrative expenses $ 130 $ 126 $ 352 $ 345
Marathon Petroleum Corporation [Member]        
Related Party Transaction [Line Items]        
General and administrative expenses 104 80 274 236
Asset under Construction [Member] | Marathon Petroleum Corporation [Member]        
Related Party Transaction [Line Items]        
Property, Plant, and Equipment, before Accumulated Depreciation, Addition $ 73 $ 64 $ 190 $ 159
v3.26.3
Related Party Assets and Liabilities (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Apr. 22, 2026
Dec. 31, 2025
Sep. 30, 2025
Related Party Transaction [Line Items]        
Other current assets $ 41   $ 51  
Right of use assets 248   276  
Unguaranteed residual assets   $ 100    
Operating lease liabilities 53   53  
Related Party [Member]        
Related Party Transaction [Line Items]        
Accounts Receivable, after Allowance for Credit Loss, Current, Related Party 814   624  
Lease receivables 228   269  
Prepaid 13   5  
Other current assets 1   1  
Current assets - related parties 1,056   899  
Long-term lease receivables 243   421  
Right of use assets 238   239  
Unguaranteed residual assets 243   263  
Long-term receivables 46   39  
Noncurrent assets - related parties 770   962  
Accounts payable [1] 346   290  
Deferred revenue 101   107  
Operating lease liabilities 2   2  
Other current liabilities 474   399  
Long-term operating lease liabilities 235   237  
Other Liabilities, Noncurrent 415   364  
Related Party [Member] | Deferred Revenue [Domain]        
Related Party Transaction [Line Items]        
Other Liabilities, Noncurrent 180   127  
Related Party [Member] | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent | Commodity Contract [Member]        
Related Party Transaction [Line Items]        
Other Derivatives Not Designated as Hedging Instruments Liabilities at Fair Value 25   0  
Revolving Credit Facility | Related Party [Member]        
Related Party Transaction [Line Items]        
Line of Credit, Current $ 0   $ 0 $ 0
[1] There were no borrowings outstanding on the MPC Loan Agreement as of September 30, 2026 or December 31, 2025.
v3.26.3
Equity - Changes in Partners Capital, Unit Rollforward (Details) - shares
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Equity [Abstract]        
Balance at December 31, 2025     1,015,702,040  
Unit-based compensation awards     134,291  
Stock Repurchased and Retired During Period, Shares (1,000,000) (2,000,000) (2,627,468) (6,000,000)
Balance at September 30, 2026 1,013,208,863   1,013,208,863  
v3.26.3
Equity (Unit Repurchases) (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Equity [Abstract]        
Stock Repurchase Program, Remaining Authorized Repurchase Amount $ 970   $ 970  
Number of common units repurchased 1,000,000 2,000,000 2,627,468 6,000,000
Cash paid for common units repurchased(1) [1] $ 50 $ 100 $ 150 $ 300
Average cost per unit(1) [1] $ 58.69 $ 50.86 $ 57.09 $ 51.20
[1] Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.
v3.26.3
Series A Preferred Units (Details)
shares in Thousands
Feb. 11, 2025
shares
Equity [Abstract]  
Partners' Capital Account, Units, Converted 6,000
v3.26.3
Equity - Cash Distributions (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 9 Months Ended
Nov. 13, 2026
Nov. 06, 2026
Oct. 27, 2026
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Distribution Made to Limited Partner [Line Items]              
Cash distributions declared per limited partner common unit       $ 1.2111 $ 1.0765 $ 3.3641 $ 2.9895
Common Unit-holders Public              
Distribution Made to Limited Partner [Line Items]              
Distribution Made to Limited Partner, Cash Distributions Declared       $ 1,226 $ 1,095 $ 3,410 $ 3,046
Common Unit-holders Public | Nonrelated Party [Member]              
Distribution Made to Limited Partner [Line Items]              
Distribution Made to Limited Partner, Cash Distributions Declared       442 397 1,232 1,110
Common Unit-holders Public | Related Party [Member]              
Distribution Made to Limited Partner [Line Items]              
Distribution Made to Limited Partner, Cash Distributions Declared       $ 784 $ 698 $ 2,178 $ 1,936
Subsequent Event              
Distribution Made to Limited Partner [Line Items]              
Distribution Made to Limited Partner, Declaration Date     Oct. 27, 2026        
Distribution Made to Limited Partner, Cash Distributions Declared     $ 1,226        
Cash distributions declared per limited partner common unit     $ 1.2111        
Subsequent Event | Common Unit-holders Public              
Distribution Made to Limited Partner [Line Items]              
Distribution date Nov. 13, 2026            
Date of record   Nov. 06, 2026          
v3.26.3
Net Income Per Limited Partner Unit - Basic and Diluted Earnings Per Unit (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Earnings Per Share [Abstract]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 1 1 1 1
Net income attributable to MPLX LP(1): [1] $ 1,164 $ 1,545 $ 3,153 $ 3,719
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic 1 1 2 2
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted 1 1 2 2
Net Income (Loss) Available to Common Stockholders, Basic 1,163 1,544 3,151 3,717
Net Income (Loss) Available to Common Stockholders, Diluted $ 1,163 $ 1,544 $ 3,151 $ 3,717
Weighted average units outstanding:        
Common - basic 1,014 1,019 1,014 1,020
Common - diluted 1,014 1,019 1,015 1,020
Per Unit Data (See Note 7)        
Common - basic $ 1.15 $ 1.52 $ 3.11 $ 3.65
Common - diluted $ 1.15 $ 1.52 $ 3.11 $ 3.65
[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.
v3.26.3
Segment Information (Details)
 9 Months Ended
Sep. 30, 2026
Segment Reporting [Abstract]  
Number of reportable segments 2
v3.26.3
Segment Information - Segment Adjusted EBITDA (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jun. 16, 2025
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax   $ 2,788 $ 2,459 $ 7,752 $ 7,275
Sales-type lease revenue   51 37 139 110
Income from equity method investments   282 186 644 542
Gain on equity method investments   0 484 0 484
Revenues   3,605 3,619 9,955 9,746
Purchased product costs   734 493 1,819 1,384
Capital Expenditures       2,325 1,203
Investments - acquisitions and contributions       720 776
Nonrelated Party [Member]          
Segment Reporting [Line Items]          
Rental income   66 68 198 196
Other Income   4 4 17 19
Crude Oil and Products Logistics          
Segment Reporting [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax   1,277 1,209 3,695 3,581
Investments in unconsolidated affiliates [1]   0 13 0 13
Crude Oil and Products Logistics | Nonrelated Party [Member]          
Segment Reporting [Line Items]          
Revenues   189 201 508 565
Natural Gas and NGL Services          
Segment Reporting [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax   1,511 1,250 4,057 3,694
Investments in unconsolidated affiliates [1]   281 227 720 549
Natural Gas and NGL Services | WPC Parent, LLC | Pro rata share of JV interest in Bay Runner Pipeline project          
Segment Reporting [Line Items]          
Investments in unconsolidated affiliates     49   49
Natural Gas and NGL Services | MXP Parent, LLC          
Segment Reporting [Line Items]          
Investments - acquisitions and contributions $ 151        
Consideration Transferred, Contingent Consideration     13    
Natural Gas and NGL Services | Nonrelated Party [Member]          
Segment Reporting [Line Items]          
Revenues   1,669 1,917 4,482 4,682
Operating Segments          
Segment Reporting [Line Items]          
Adjusted EBITDA   1,859 1,766 5,363 5,213
Operating Segments | Crude Oil and Products Logistics          
Segment Reporting [Line Items]          
Rental income   298 239 829 682
Sales-type lease revenue   77 113 264 344
Income from equity method investments   83 71 197 186
Other Income   33 28 91 94
Revenues [2]   1,768 1,660 5,076 4,887
Operating Expenses   582 553 1,686 1,613
Segment Reporting, Other Segment Item, Amount [3]   (18) (30) (86) (98)
Adjusted EBITDA [4]   1,204 1,137 3,476 3,372
Capital Expenditures   174 147 409 391
Operating Segments | Natural Gas and NGL Services          
Segment Reporting [Line Items]          
Rental income   58 57 176 169
Sales-type lease revenue   51 37 139 110
Income from equity method investments   199 115 447 356
Gain on equity method investments   0 484 [5] 0 484 [5]
Other Income   18 16 60 46
Revenues [2]   1,837 1,959 4,879 4,859
Purchased product costs   734 493 1,819 1,384
Operating Expenses   435 426 1,281 1,293
Segment Reporting, Other Segment Item, Amount [3]   13 411 (108) 341
Adjusted EBITDA [4]   655 629 1,887 1,841
Capital Expenditures   667 447 1,916 812
Service [Member] | Operating Segments | Crude Oil and Products Logistics          
Segment Reporting [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax   1,272 1,205 3,679 3,569
Service [Member] | Operating Segments | Natural Gas and NGL Services          
Segment Reporting [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax   653 639 1,894 1,837
Product [Member] | Operating Segments | Crude Oil and Products Logistics          
Segment Reporting [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax   5 4 16 12
Product [Member] | Operating Segments | Natural Gas and NGL Services          
Segment Reporting [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax   $ 858 $ 611 $ 2,163 $ 1,857
[1] Investments in unconsolidated affiliates for the three and nine months ended September 30, 2026 and September 30, 2025 include cash contributions to several joint ventures to fund current growth capital projects. Investments in unconsolidated affiliates for the nine months ended September 30, 2025 exclude $151 million related to the acquisition of an additional interest in the joint venture that owns and operates the Matterhorn Express Pipeline, and the three and nine months ended September 30, 2025 exclude a $49 million capital contribution to WPC Parent, LLC to purchase Enbridge’s special membership interest in the Bay Runner Pipeline project and a $13 million payment related to earnout associated with MXP Parent, LLC.
[2] Within the total segment revenues and other income amounts presented above, third-party revenues for the Crude Oil and Products Logistics segment were $189 million and $508 million for the three and nine months ended September 30, 2026, respectively, and $201 million and $565 million for the three and nine months ended September 30, 2025, respectively. Third-party revenues for the Natural Gas and NGL Services segment were $1,669 million and $4,482 million for the three and nine months ended September 30, 2026, respectively, and $1,917 million and $4,682 million for the three and nine months ended September 30, 2025, respectively.
[3] Other segment items in the Crude Oil and Products Logistics segment include income from equity method investments, distributions and adjustments related to equity method investments, equity-based compensation and other miscellaneous items. Other segment items in the Natural Gas and NGL Services segment include income from equity method investments, distributions and adjustments related to equity method investments, unrealized derivative gain/(loss) and other miscellaneous items.
[4] See below for the reconciliation from Segment Adjusted EBITDA to Net income.
[5] The three and nine months ended September 30, 2025 represent the gain on remeasurement of our existing equity investment in BANGL in conjunction with the BANGL Acquisition.
v3.26.3
Segment Information - Reconciliation to Net Income (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]        
Depreciation and Amortization [1] $ 378 $ 346 $ 1,101 $ 996
Interest and Other Financial Costs 300 243 880 706
Income from equity method investments 282 186 644 542
Business Combination, Separately Recognized Transaction, Acquisition-Related Cost, Expensed 0 (21) [2] 0 (21) [2]
Net income 1,174 1,555 3,183 3,749
Operating Segments        
Segment Reporting [Line Items]        
Adjusted EBITDA 1,859 1,766 5,363 5,213
Segment Reconciling Items [Member]        
Segment Reporting [Line Items]        
Gain on equity method investment 0 484 0 484
Distributions/adjustments related to equity method investments 250 251 735 707
Adjusted EBITDA attributable to noncontrolling interests 11 11 33 33
Other Noncash Income (Expense) [3] 50 31 141 93
Crude Oil and Products Logistics        
Segment Reporting [Line Items]        
Depreciation and Amortization 154 139 443 407
Crude Oil and Products Logistics | Operating Segments        
Segment Reporting [Line Items]        
Adjusted EBITDA [4] 1,204 1,137 3,476 3,372
Income from equity method investments 83 71 197 186
Natural Gas and NGL Services        
Segment Reporting [Line Items]        
Depreciation and Amortization 224 207 658 589
Natural Gas and NGL Services | Operating Segments        
Segment Reporting [Line Items]        
Adjusted EBITDA [4] 655 629 1,887 1,841
Income from equity method investments $ 199 $ 115 $ 447 $ 356
[1] Depreciation and amortization attributable to Crude Oil and Products Logistics was $154 million and $443 million for the three and nine months ended September 30, 2026, respectively, and $139 million and $407 million for the three and nine months ended September 30, 2025, respectively. Depreciation and amortization attributable to Natural Gas and NGL Services was $224 million and $658 million for the three and nine months ended September 30, 2026, respectively, and $207 million and $589 million for the three and nine months ended September 30, 2025, respectively.
[2] Transaction-related costs include costs associated with acquisition and divestiture-related activities, including significant transactions discussed in Note 3.
[3] Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.
[4] See below for the reconciliation from Segment Adjusted EBITDA to Net income.
v3.26.3
Property, Plant and Equipment (Summary of Property, Plant and Equipment) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Property, Plant, and Equipment [Line Items]          
Gross PP&E $ 34,065   $ 34,065   $ 31,759
Accumulated Depreciation 10,983   10,983   10,061
Net PP&E 23,082   23,082   21,698
Depreciation 335 $ 310 970 $ 897  
Crude Oil and Products Logistics          
Property, Plant, and Equipment [Line Items]          
Gross PP&E 14,369   14,369   13,809
Accumulated Depreciation 5,452   5,452   5,058
Net PP&E 8,917   8,917   8,751
Natural Gas and NGL Services          
Property, Plant, and Equipment [Line Items]          
Gross PP&E 19,696   19,696   17,950
Accumulated Depreciation 5,531   5,531   5,003
Net PP&E $ 14,165   $ 14,165   $ 12,947
v3.26.3
Fair Values - Recurring - Balance Sheet Location Table (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Sep. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value $ 291   $ 285
Commodity Contract [Member] | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent | Related Party [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Other Derivatives Not Designated as Hedging Instruments Liabilities at Fair Value 25 $ 0  
Level 3 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivative Liability, Subject to Master Netting Arrangement, before Offset 53 41  
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value 291 277  
Level 3 [Member] | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Business Combination, Contingent Consideration, Liability 238 236  
Level 3 [Member] | Embedded Derivative [Member] | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivative Liability, Subject to Master Netting Arrangement, before Offset 13 6  
Level 3 [Member] | Embedded Derivative [Member] | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivative Liability, Subject to Master Netting Arrangement, before Offset 40 $ 35  
Fair Value, Inputs, Level 2 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivative Liability 25    
Fair Value, Inputs, Level 2 [Member] | Commodity Contract [Member] | Fair Value, Recurring [Member] | Related Party [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Other Derivatives Not Designated as Hedging Instruments Liabilities at Fair Value $ 25    
v3.26.3
Fair Values - Recurring - Significant Unobservable Inputs in Level 3 Valuation (Details)
$ in Millions
 9 Months Ended
Sep. 30, 2026
$ / gal
Jul. 01, 2025
USD ($)
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]    
Derivative, Contract Term 5 years  
BANGL, LLC    
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]    
Business Combination, Contingent Consideration, Range of Outcomes, Maximum, Amount | $   $ 275
Level 3 [Member]    
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]    
Derivative, Average Forward Price 0.89  
Fair Value Inputs Probability of Renewal 100.00%  
Minimum [Member] | Level 3 [Member]    
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]    
Derivative, Forward Price 0.64  
Maximum [Member] | Level 3 [Member]    
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]    
Derivative, Forward Price 2.04  
v3.26.3
Changes in Level 3 Fair Value Measurements (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Beginning balance $ (282) $ (55) $ (277) $ (58)
Business Combination, Contingent Consideration, Liability 0 (234) [1] 0 (234) [1],[2]
Unrealized and realized gain/(loss) included in Net income(2) [3] (13) 2 (23) (1)
Settlements 4 2 9 8
Ending balance $ (291) $ (285) $ (291) $ (285)
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 Purchased product costs Purchased product costs
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]        
[1] Liability recorded in the third quarter of 2025 related to the BANGL Acquisition earnout provision.
[2] See Note 3 - BANGL, LLC Acquisition.
[3] Gain/(loss) on derivatives embedded in commodity contracts are recorded in Purchased product costs in the Consolidated Statements of Income.
v3.26.3
Fair Value Measurements Gain/Loss Included in Earnings Relating to Assets Still Held at End of Period (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Fair Value Disclosures [Abstract]        
The amount of total gain/(loss) for the period included in earnings attributable to the change in unrealized gain/(loss) relating to liabilities still held at end of period $ (12) $ 2 $ (19) $ (1)
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 Purchased product costs Purchased product costs
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]        
v3.26.3
Fair Values - Reported (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-Term Debt, Fair Value [1] $ 24,381 $ 24,887
Carrying Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-Term Debt, Fair Value [1] $ 26,797 $ 25,821
[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.
v3.26.3
Derivative Financial Instruments - Embedded Derivatives in Commodity Contracts (Details)
 9 Months Ended
Sep. 30, 2026
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.
Derivative, Contract Term 5 years
Embedded Derivative [Member]  
Derivative [Line Items]  
Number of Renewals 1
Derivative, Contract Term 5 years
v3.26.3
Derivatives (Classification of Gross Fair Values of Derivative Instruments, Excluding Cash Collateral) (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent | Nonrelated Party [Member]    
Derivative [Line Items]    
Embedded Derivative, Fair Value of Embedded Derivative Liability [1] $ 13 $ 6
Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesNoncurrent | Nonrelated Party [Member]    
Derivative [Line Items]    
Embedded Derivative, Fair Value of Embedded Derivative Liability [1] 40 35
Commodity Contract [Member] | Balance Sheet Location [Axis]: us-gaap:OtherLiabilitiesCurrent | Related Party [Member]    
Derivative [Line Items]    
Other Derivatives Not Designated as Hedging Instruments Liabilities at Fair Value $ 25 $ 0
[1] Includes embedded derivatives.
v3.26.3
Derivatives Financial Instruments - Derivative Income Statement Location (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Derivative [Line Items]        
Derivative, Gain (Loss) on Derivative, Net $ (39) $ 2 $ (89) $ (1)
Commodity Contract [Member] | Not Designated as Hedging Instrument        
Derivative [Line Items]        
Derivative, Gain (Loss) on Derivative, Net $ (4) $ 0 $ (10) $ 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 Revenue from Contract with Customer, Excluding Assessed Tax - Third parties
Commodity Contract [Member] | Not Designated as Hedging Instrument, Economic Hedge        
Derivative [Line Items]        
Derivative, Gain (Loss) on Derivative, Net $ (25) $ 0 $ (58) $ 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 Revenue from Contract with Customer, Excluding Assessed Tax - Third parties
Embedded Derivative [Member] | Not Designated as Hedging Instrument        
Derivative [Line Items]        
Derivative, Gain (Loss) on Derivative, Net $ (10) $ 2 $ (21) $ (1)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Purchased product costs Purchased product costs Purchased product costs Purchased product costs
Income Statement Location [Axis]: us-gaap:CostDirectMaterial | Embedded Derivative [Member] | Not Designated as Hedging Instrument        
Derivative [Line Items]        
Realized gain (loss) $ (3) $ (2) $ (8) $ (8)
Unrealized Gain (Loss) on Derivatives and Commodity Contracts (7) 4 (13) 7
Income Statement Location [Axis]: mplx:RevenueFromContractWithCustomerExcludingAssessedTaxThirdParties | Commodity Contract [Member] | Not Designated as Hedging Instrument        
Derivative [Line Items]        
Realized gain (loss) (2) 0 (6) 0
Unrealized Gain (Loss) on Derivatives and Commodity Contracts (2) 0 (4) 0
Income Statement Location [Axis]: mplx:RevenueFromContractWithCustomerExcludingAssessedTaxThirdParties | Commodity Contract [Member] | Not Designated as Hedging Instrument, Economic Hedge        
Derivative [Line Items]        
Realized gain (loss) (16) 0 (37) 0
Unrealized Gain (Loss) on Derivatives and Commodity Contracts $ (9) $ 0 $ (21) $ 0
v3.26.3
Debt - Summary of Outstanding Borrowings (Detail) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Aug. 11, 2025
Debt Instrument [Line Items]      
Finance lease obligations $ 5 $ 6  
Debt and Lease Obligation 27,005 26,006  
Unamortized debt issuance costs (194) (174)  
Unamortized discount (203) (179)  
Amounts due within one year 2 1,502  
Total long-term debt due after one year 26,606 24,151  
Senior Notes [Member]      
Debt Instrument [Line Items]      
Debt Instrument, Face Amount     $ 4,500
MPLX LP [Member]      
Debt Instrument [Line Items]      
Senior Notes 26,969 25,969  
ANDX LP [Member]      
Debt Instrument [Line Items]      
Senior Notes $ 31 $ 31  
v3.26.3
Credit Agreement (Detail) - USD ($)
$ in Millions
Sep. 30, 2026
Apr. 07, 2026
Debt Instrument [Line Items]    
Line of Credit Facility, Remaining Borrowing Capacity, Percentage 100.00%  
MPLX Revolving Credit Facility due June 2027    
Debt Instrument [Line Items]    
Long-term Line of Credit $ 0  
Line of Credit Facility, Maximum Borrowing Capacity   $ 2,000
Letters of Credit Outstanding, Amount 1  
Line of Credit Facility, Remaining Borrowing Capacity 2,500  
MPLX Revolving Credit Facility due April 2031    
Debt Instrument [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity 2,500  
MPLX Revolving Credit Facility due April 2031 | Letter of Credit    
Debt Instrument [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity 150  
MPLX Revolving Credit Facility due April 2031 | Swing-line Loan    
Debt Instrument [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity $ 150  
v3.26.3
Senior Notes (Details) - Senior Notes [Member] - USD ($)
$ in Millions
Sep. 23, 2026
Aug. 24, 2026
Mar. 02, 2026
Feb. 12, 2026
Sep. 30, 2026
Aug. 11, 2025
Debt Instrument [Line Items]            
Debt Instrument, Face Amount           $ 4,500
Senior Note Due April 20236            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage       5.30%    
Debt Instrument, Face Amount       $ 1,000    
Debt Instrument, Issuance Date       Feb. 12, 2026    
Percent of Par       99.678%    
Senior Note Due April 2056            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage       6.10%    
Debt Instrument, Face Amount       $ 500    
Debt Instrument, Issuance Date       Feb. 12, 2026    
Percent of Par       98.453%    
Senior Notes Due March 2026            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage     1.75%      
Repayments of Debt     $ 1,500      
Senior Notes Due November 2029            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage   4.70%        
Debt Instrument, Face Amount   $ 1,250        
Debt Instrument, Issuance Date   Aug. 24, 2026        
Percent of Par   99.312%        
Senior Notes Due May 2032            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage   5.00%        
Debt Instrument, Face Amount   $ 500        
Debt Instrument, Issuance Date   Aug. 24, 2026        
Percent of Par   98.972%        
Senior Notes Due November 2036            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage   5.50%        
Debt Instrument, Face Amount   $ 500        
Debt Instrument, Issuance Date   Aug. 24, 2026        
Percent of Par   98.066%        
MPLX LP [Member] | Senior Notes Due March 2027            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage 4.125%          
Repayments of Debt $ 1,250          
Minimum [Member]            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage         2.65%  
Maximum [Member]            
Debt Instrument [Line Items]            
Debt Instrument, Interest Rate, Stated Percentage         6.20%  
v3.26.3
Interest and Other Financial Costs (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Other Income and Expenses [Abstract]        
Interest expense $ 330 $ 279 $ 966 $ 767
Other financial costs 12 (9) 32 14
Interest income (12) (16) (42) (50)
Capitalized interest (30) (11) (76) (25)
Interest and Debt Expense, Total $ 300 $ 243 $ 880 $ 706
v3.26.3
Revenue Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax $ 2,788 $ 2,459 $ 7,752 $ 7,275
Revenue Not from Contract with Customer, Other [1] 817 1,160 2,203 2,471
Revenues 3,605 3,619 9,955 9,746
Crude Oil and Products Logistics        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,277 1,209 3,695 3,581
Natural Gas and NGL Services        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,511 1,250 4,057 3,694
Service [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 740 750 2,154 2,153
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 1,185 1,094 3,419 3,253
Service [Member] | Crude Oil and Products Logistics        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 94 115 279 332
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 1,178 1,090 3,400 3,237
Service [Member] | Natural Gas and NGL Services        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 646 635 1,875 1,821
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 7 4 19 16
Service, Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 46 [2] 64 135 [2] 233
Service, Other [Member] | Crude Oil and Products Logistics        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 0 0 0 0
Service, Other [Member] | Natural Gas and NGL Services        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 46 [2] 64 135 [2] 233
Product [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 669 [2] 525 1,703 [2] 1,510
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 148 26 341 126
Product [Member] | Crude Oil and Products Logistics        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 1 1 4 3
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 4 3 12 9
Product [Member] | Natural Gas and NGL Services        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 668 [2] 524 1,699 [2] 1,507
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties $ 144 $ 23 $ 329 $ 117
[1] Non-ASC 606 Revenue and other income includes rental income, sales-type lease revenue, income from equity method investments, and other income.
[2] Contains non-ASC 606 revenue from derivative-related activity as disclosed in Note 11.
v3.26.3
Revenue Contract Balances (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Contract assets $ 1 $ 12 $ 15 $ 2
Contract assets, additions/(deletions) (14) 10    
Contract with Customer, Asset, Reclassified to Receivable [1] 0 0    
Long-term contract assets 4 4 4 0
Contract with Customer, Asset Increase (Decrease), Noncurrent 0 4    
Contract With Customer Non Current Asset Reclassified To Receivable [1] 0 0    
Liability, change in timeframe, performance obligation satisfied, revenue recognized 0 0    
Nonrelated Party [Member]        
Deferred revenue 20 47 13 84
Deferred revenue, revenue recognized [1] (19) (59)    
Deferred Revenue, Additions 26 22    
Long-term deferred revenue, additions/(deletions) (13) (15)    
Long-term deferred revenue, revenue recognized [1] 0 0    
Deferred Revenue from Contracts with Customers, Noncurrent 104 300 117 315
Related Party [Member]        
Deferred revenue 101   107  
Deferred revenue, revenue recognized [1] (62) (62)    
Deferred Revenue, Additions 63 66    
Deferred Revenue from Contracts with Customers, Current 67 75 66 71
Long-term deferred revenue, additions/(deletions) 3 1    
Long-term deferred revenue, revenue recognized [1] 0 0    
Deferred Revenue from Contracts with Customers, Noncurrent $ 48 $ 45 $ 45 $ 44
[1] No significant revenue was recognized related to past performance obligations in the periods presented.    
v3.26.3
Revenue Remaining Performance Obligations (Details)
$ in Millions
Sep. 30, 2026
USD ($)
Revenue from Contract with Customer [Abstract]  
Contract with customer, liability $ 239
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, Remaining Performance Obligation, Amount $ 5,400
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 6 months
Revenue, Remaining Performance Obligation, Amount $ 500
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 1 year
Revenue, Remaining Performance Obligation, Amount $ 2,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 1 year
Revenue, Remaining Performance Obligation, Amount $ 800
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 1 year
Revenue, Remaining Performance Obligation, Amount $ 500
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 1 year
Revenue, Remaining Performance Obligation, Amount $ 400
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2031-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 14 years
Revenue, Remaining Performance Obligation, Amount $ 1,200
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2044-06-30  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 19 years
v3.26.3
Leases (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Apr. 22, 2026
Dec. 31, 2025
Lessor, Lease, Description [Line Items]      
Lessor, Operating Lease, Payment to be Received, Year One $ 270    
Lessor, Operating Lease, Payment to be Received, Year Two 1,019    
Lessor, Operating Lease, Payment to be Received, Year Three 705    
Lessor, Operating Lease, Payment to be Received, Year Four 546    
Lessor, Operating Lease, Payment to be Received, Year Five 533    
Lessor, Operating Lease, Payment to be Received, after Year Five 948    
Lessor, Operating Lease, Payment to be Received 4,021    
Sales-type Lease, Lease Receivable   $ 102  
Unguaranteed residual assets   100  
Net investment in sales-type lease reclassified to PP&E   $ 216  
Related Party [Member]      
Lessor, Lease, Description [Line Items]      
Lessor, Operating Lease, Payment to be Received, Year One 246    
Lessor, Operating Lease, Payment to be Received, Year Two 935    
Lessor, Operating Lease, Payment to be Received, Year Three 630    
Lessor, Operating Lease, Payment to be Received, Year Four 473    
Lessor, Operating Lease, Payment to be Received, Year Five 474    
Lessor, Operating Lease, Payment to be Received, after Year Five 763    
Lessor, Operating Lease, Payment to be Received 3,521    
Unguaranteed residual assets 243   $ 263
Nonrelated Party [Member]      
Lessor, Lease, Description [Line Items]      
Lessor, Operating Lease, Payment to be Received, Year One 24    
Lessor, Operating Lease, Payment to be Received, Year Two 84    
Lessor, Operating Lease, Payment to be Received, Year Three 75    
Lessor, Operating Lease, Payment to be Received, Year Four 73    
Lessor, Operating Lease, Payment to be Received, Year Five 59    
Lessor, Operating Lease, Payment to be Received, after Year Five 185    
Lessor, Operating Lease, Payment to be Received $ 500    
v3.26.3
Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
 [3]
Sep. 30, 2026
Sep. 30, 2025
Supplemental Cash Flow Elements [Abstract]        
Interest paid (net of amounts capitalized)     $ 931 $ 705
Income taxes paid     4 3
Payments on operating leases     50 47
Principal payments under finance lease obligations     6 2
Net transfers of property, plant and equipment to lease receivable     187 123
Contribution of assets(1)     0 115 [1]
ROU assets obtained in exchange for new operating lease obligations     10 30
ROU assets obtained in exchange for new finance lease obligations     4 3
Book value of equity method investment(2)     0 282 [2]
Contingent consideration(3) $ 0 $ 234 $ 0 $ 234 [3],[4]
[1] Represents the book value of assets contributed by MPLX to a joint venture.
[2] Represents the book value of MPLX’s equity method investment in BANGL, prior to MPLX buying out the remaining interest in the entity. See Note 3 - BANGL, LLC Acquisition.
[3] Liability recorded in the third quarter of 2025 related to the BANGL Acquisition earnout provision.
[4] See Note 3 - BANGL, LLC Acquisition.
v3.26.3
Supplemental Cash Flow Information - Summary of Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Supplemental Cash Flow Elements [Abstract]    
Additions to property, plant and equipment $ 2,195 $ 1,094
Increase in capital accruals 130 131
Other Adjustments to Capital Expenditures 0 (22)
Total capital expenditures $ 2,325 $ 1,203
v3.26.3
Commitments and Contingencies - Additional Information (Detail) - USD ($)
$ in Millions
 1 Months Ended 9 Months Ended
Dec. 31, 2020
Jul. 31, 2020
Sep. 30, 2026
Dec. 31, 2025
Commitments And Contingencies [Line Items]        
Accrued liabilities for environmental remediation     $ 17 $ 21
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]     Other current liabilities, Other long-term liabilities Other current liabilities, Other long-term liabilities
Loss Contingency, Damages Sought, Value   $ 187    
Loss Contingency, Damages Paid, Value $ 4      
Guarantor Obligations, Origin and Purpose     GuaranteesDakota Access Pipeline We hold a 9.19 percent indirect interest in Dakota Access, which owns and operates the Bakken Pipeline system. We have entered into a Contingent Equity Contribution Agreement whereby we, along with the other joint venture owners in the Bakken Pipeline system, have agreed to make equity contributions to the joint venture upon vacatur of an easement that results in a shutdown of the pipeline to allow the entities that own and operate the Bakken Pipeline system to satisfy their senior note payment obligations. As of September 30, 2026, our maximum potential undiscounted payments under the Contingent Equity Contribution Agreement were approximately $78 million.  
Bakken Pipeline System [Member] | Guarantee of Indebtedness of Others [Member] | Financial Guarantee [Member]        
Commitments And Contingencies [Line Items]        
Guarantor Obligations, Maximum Exposure, Undiscounted     $ 78  
v3.26.3
Subsequent Events (Details) - Disposal Group, Not Discontinued Operations - St. Paul Park and Mandan logistics operations - USD ($)
$ in Millions
Nov. 02, 2026
Sep. 30, 2026
Subsequent Event [Line Items]    
Disposal Group, Including Discontinued Operation, Carrying Value of Net Assets   $ 422
Subsequent Event    
Subsequent Event [Line Items]    
Disposal Group, Including Discontinued Operation, Consideration $ 750