MPLX LP, 10-Q filed on 11/5/2024
Quarterly Report
v3.24.3
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2024
Oct. 31, 2024
Cover [Abstract]    
Document Fiscal Year Focus 2024  
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, 2024  
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   1,018,812,097
v3.24.3
Consolidated Statements of Income - USD ($)
shares in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Sales-type lease revenue $ 34 $ 34 $ 102 $ 101
Sales-type lease revenue - related parties 118 129 359 379
Income from equity method investments 149 159 631 438
Total revenues and other income 2,972 2,912 8,870 8,315
Purchases - related parties 402 442 1,162 1,160
Depreciation and amortization [1] 322 301 959 907
General and administrative expenses 107 102 323 280
Other taxes 32 44 99 102
Total costs and expenses 1,697 1,758 4,925 4,790
Income from operations 1,275 1,154 3,945 3,525
Net interest and other financial costs 226 225 692 701
Income before income taxes 1,049 929 3,253 2,824
Provision for income taxes 2 1 5 2
Net income 1,047 928 3,248 2,822
Less: Net income attributable to noncontrolling interests 10 10 30 28
Net income attributable to MPLX LP [2] 1,037 918 3,218 2,794
Limited partners' interest in net income attributable to MPLX LP $ 1,031 $ 893 $ 3,197 $ 2,718
Net income attributable to MPLX LP per limited partner unit:        
Common - basic $ 1.01 $ 0.89 $ 3.14 $ 2.70
Common - diluted $ 1.01 $ 0.89 $ 3.14 $ 2.70
Weighted average limited partner units outstanding:        
Common - basic 1,020 1,001 1,016 1,001
Common - diluted 1,020 1,001 1,016 1,001
Nonrelated Party [Member]        
Rental income $ 63 $ 61 $ 187 $ 181
Other Income 7 7 58 28
Rental cost of sales 22 20 61 60
Related Party [Member]        
Rental income 216 207 644 612
Other Income 40 32 117 90
Rental cost of sales 5 8 14 24
General and administrative expenses 73 72 217 197
Service [Member]        
Revenue from Contract with Customer, Excluding Assessed Tax - Third parties 709 641 2,050 1,881
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 1,066 1,038 3,102 2,962
Service, Other [Member]        
Revenue from Contract with Customer, Excluding Assessed Tax - Third parties 86 75 265 214
Product [Member]        
Revenue from Contract with Customer, Excluding Assessed Tax - Third parties 433 478 1,191 1,274
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 51 51 164 155
Natural Gas, Midstream [Member]        
Purchased product costs 403 474 1,148 1,234
Oil and Gas Service        
Cost of revenues (excludes items below) 404 367 1,159 1,023
Series A Preferred Stock [Member]        
Dividends, Preferred Stock 6 25 21 71
Series B Preferred Stock [Member]        
Dividends, Preferred Stock $ 0 $ 0 $ 0 $ 5
[1] Depreciation and amortization attributable to L&S was $132 million and $393 million for the three and nine months ended September 30, 2024, respectively, and $130 million and $399 million for the three and nine months ended September 30, 2023, respectively. Depreciation and amortization attributable to G&P was $190 million and $566 million for the three and nine months ended September 30, 2024, respectively, and $171 million and $508 million for the three and nine months ended September 30, 2023, respectively.
[2] Allocation of net income attributable to MPLX LP assumes all earnings for the period have been distributed based on the distribution priorities applicable to the period.
v3.24.3
Consolidated Statements of Comprehensive Income - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Net income $ 1,047 $ 928 $ 3,248 $ 2,822
Other Comprehensive Income (Loss), Net of Tax 0 0 1 4
Comprehensive income 1,047 928 3,249 2,826
Less comprehensive income attributable to:        
Noncontrolling interests 10 10 30 28
Comprehensive income attributable to MPLX LP $ 1,037 $ 918 $ 3,219 $ 2,798
v3.24.3
Consolidated Balance Sheets - USD ($)
$ in Millions
Sep. 30, 2024
Dec. 31, 2023
Assets    
Cash and cash equivalents $ 2,426 $ 1,048
Receivables, net 742 823
Inventories 171 159
Other current assets 37 30
Total current assets 4,218 2,808
Equity method investments 4,558 3,743
Property, plant and equipment, net 19,153 19,264
Intangibles, net 551 654
Goodwill 7,645 7,645
Right of use assets, net 271 264
Other noncurrent assets 984 990
Total assets 38,515 36,529
Liabilities    
Accounts payable 120 153
Accrued liabilities 271 300
Accrued property, plant and equipment 190 216
Long-term debt due within one year 2,836 1,135
Accrued interest payable 220 242
Operating lease liabilities 49 45
Total current liabilities 4,267 2,624
Long-term deferred revenue 326 347
Long-term debt 19,250 19,296
Deferred income taxes 16 16
Long-term operating lease liabilities 217 211
Total liabilities 24,533 22,945
Commitments and contingencies (see Note 16)
Series A Preferred Units 203 895
Equity    
Accumulated other comprehensive loss (3) (4)
Total MPLX LP partners’ capital 13,547 12,454
Noncontrolling interests 232 235
Total equity 13,779 12,689
Total liabilities, preferred units and equity 38,515 36,529
Related Party [Member]    
Assets    
Receivables, net 625 587
Current assets - related parties 842 748
Other current assets 0 7
Right of use assets, net 226 227
Noncurrent assets - related parties 1,135 1,161
Liabilities    
Operating lease liabilities 1 1
Other current liabilities 354 360
Long-term deferred revenue 95 99
Long-term liabilities - related parties 320 325
Equity    
Limited Partners' Capital Account 4,172 3,758
Nonrelated Party [Member]    
Liabilities    
Other current liabilities 227 173
Long-term deferred revenue 322 344
Long-term liabilities - related parties 137 126
Equity    
Limited Partners' Capital Account $ 9,378 $ 8,700
v3.24.3
Consolidated Balance Sheets (Parenthetical) - shares
Sep. 30, 2024
Dec. 31, 2023
Units Outstanding 1,019,246,237 1,003,498,875
Series A Preferred Stock [Member]    
Preferred Units, Outstanding 6,000,000 27,000,000
Common Unit-holders Public | Nonrelated Party [Member]    
Units Outstanding 372,000,000 356,000,000
Common Unit-holders Public | Related Party [Member]    
Units Outstanding 647,000,000 647,000,000
v3.24.3
Consolidated Statements of Cash Flows - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Operating activities:    
Net income $ 3,248 $ 2,822
Amortization of Debt Issuance Costs and Discounts 41 42
Adjustments to reconcile net income to net cash provided by operating activities:    
Depreciation and amortization [1] 959 907
Deferred income taxes 0 (1)
Gain on sales-type leases and equity method investments 20 0
Loss/(gain) on disposal of assets 3 (15)
Income from equity method investments (631) (438)
Distributions from unconsolidated affiliates 596 526
Change in fair value of derivatives 7 (3)
Changes in:    
Receivables 138 (31)
Inventories (11) (15)
Current accounts payable and other current assets and liabilities (54) (36)
Assets and liabilities - related parties (23) 89
Right of use assets and operating lease liabilities 3 4
Deferred revenue 2 65
All other, net 13 (8)
Net cash provided by operating activities 4,271 3,908
Net Cash Provided by (Used in) Investing Activities [Abstract]    
Additions to property, plant and equipment (748) (662)
Acquisitions, net of cash acquired 622 0
Disposal of assets 0 25
Payments to Acquire Interest in Joint Venture 414 90
- redemptions, repayments, return of capital and sales proceeds 138 0
Net cash used in investing activities (1,646) (727)
Net Cash Provided by (Used in) Financing Activities [Abstract]    
Long-term debt borrowings 1,630 1,589
Long-term debt - repayments (1) (1,001)
Debt issuance costs 15 15
Unit repurchases [2] (226) 0
Distributions to noncontrolling interests (33) (30)
Distributions to unitholders and general partner (2,585) (2,329)
Contributions from MPC 26 20
All other, net (5) (3)
Net cash used in financing activities (1,247) (2,459)
Net change in cash, cash equivalents and restricted cash 1,378 722
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance 1,048 238
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Ending Balance 2,426 960
Series A Preferred Stock [Member]    
Net Cash Provided by (Used in) Financing Activities [Abstract]    
Distributions to preferred unitholders (38) (69)
Series B Preferred Stock [Member]    
Net Cash Provided by (Used in) Financing Activities [Abstract]    
Redemption of Series B preferred units 0 (600)
Distributions to preferred unitholders $ 0 $ (21)
[1] Depreciation and amortization attributable to L&S was $132 million and $393 million for the three and nine months ended September 30, 2024, respectively, and $130 million and $399 million for the three and nine months ended September 30, 2023, respectively. Depreciation and amortization attributable to G&P was $190 million and $566 million for the three and nine months ended September 30, 2024, respectively, and $171 million and $508 million for the three and nine months ended September 30, 2023, respectively.
[2] Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.
v3.24.3
Consolidated Statements of Equity and Series A Preferred Units (Consolidated Statements of Equity) - USD ($)
$ in Millions
Total
Common Unit-holders Public
Common Unit-holder MPC
Series B Preferred Unit-holders
Accumulated Other Comprehensive Loss
Non-controlling Interests
Beginning Balance at Dec. 31, 2022 $ 12,546 $ 8,413 $ 3,293 $ 611 $ (8) $ 237
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Net income 929 323 592 5 0 9
Redemption of Series B preferred units (600) (2) (3) (595) 0 0
Distributions (808) (275) (502) (21) 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders           (10)
Contributions 8 0 8 0 0 0
Other 5 0 0 0 4 1
Ending Balance at Mar. 31, 2023 12,080 8,459 3,388 0 (4) 237
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Net income 919 322 588 0 0 9
Distributions (785) (274) (502) 0 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders           (9)
Contributions 5 0 5 0 0 0
Other 2 1 1 0 0 0
Ending Balance at Jun. 30, 2023 12,221 8,508 3,480 0 (4) 237
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Net income 903 297 596 0 0 10
Distributions (787) (274) (502) 0 0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders           (11)
Contributions 7 0 7 0 0 0
Other 2 2 0 0 0 0
Ending Balance at Sep. 30, 2023 12,346 8,533 3,581 $ 0 (4) 236
Beginning Balance at Dec. 31, 2023 12,689 8,700 3,758   (4) 235
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Net income 1,005 355 640   0 10
Unit repurchases (75) (75) 0   0 0
Conversion of Series A preferred units 321 321 0   0 0
Distributions (864) (303) (550)   0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders           (11)
Contributions 10 0 10   0 0
Other 0 (1) 0   1 0
Ending Balance at Mar. 31, 2024 13,086 8,997 3,858   (3) 234
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Net income 1,181 425 746   0 10
Unit repurchases (75) (75) 0   0 0
Conversion of Series A preferred units 354 354 0   0 0
Distributions (875) (314) (550)   0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders           (11)
Contributions 8 0 8   0 0
Other 5 5 0   0 0
Ending Balance at Jun. 30, 2024 13,684 9,392 4,062   (3) 233
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Net income 1,041 377 654   0 10
Unit repurchases (76) (76) 0   0 0
Distributions (879) (317) (551)   0  
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders           (11)
Contributions 7 0 7   0 0
Other 2 2 0   0 0
Ending Balance at Sep. 30, 2024 $ 13,779 $ 9,378 $ 4,172   $ (3) $ 232
v3.24.3
Consolidated Statements of Equity and Series A Preferred Units (Temporary Equity) - USD ($)
$ in Millions
Total
Series A Preferred Unit-holders
Beginning Balance at Dec. 31, 2022   $ 968
Net income   23
Distributions   23
Ending Balance at Mar. 31, 2023   968
Net income   23
Distributions   23
Ending Balance at Jun. 30, 2023   968
Net income   25
Distributions   23
Ending Balance at Sep. 30, 2023   970
Beginning Balance at Dec. 31, 2023 $ 895 895
Net income   10
Conversion of Series A preferred units   (321)
Distributions   23
Ending Balance at Mar. 31, 2024   561
Net income   5
Conversion of Series A preferred units   (354)
Distributions   10
Ending Balance at Jun. 30, 2024   202
Net income   6
Distributions   5
Ending Balance at Sep. 30, 2024 $ 203 $ 203
v3.24.3
Description of the Business and Basis of Presentation
 9 Months Ended
Sep. 30, 2024
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, processing and transportation of natural gas; and the transportation, fractionation, storage and marketing of NGLs. MPLX’s principal executive office is located in Findlay, Ohio. MPLX was formed on March 27, 2012 as a Delaware limited partnership and completed its initial public offering on October 31, 2012.
MPLX’s business consists of two segments based on the nature of services it offers: Logistics and Storage (“L&S”), which relates primarily to crude oil, refined products, other hydrocarbon-based products and renewables; and Gathering and Processing (“G&P”), which relates primarily to natural gas and NGLs. See Note 8 for additional information regarding the operations and results of these segments.
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, 2023. The results of operations for the three and nine months ended September 30, 2024 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.
Certain prior period financial statement amounts have been reclassified to conform to current period presentation.
v3.24.3
Accounting Standards
 9 Months Ended
Sep. 30, 2024
Accounting Standards Update and Change in Accounting Principle [Abstract]  
Accounting Standards Accounting Standards and Disclosure Rules
Recently Adopted
During the first quarter of 2024, we adopted ASU 2023-01, Leases (Topic 842): Common Control Arrangements. The adoption of this ASU did not have a material impact on our financial statements or disclosures.
Not Yet Adopted
ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses
In November 2024, the FASB issued an ASU to require more detailed information about specified categories of expenses (purchases of inventory, employee compensation, depreciation, amortization, and depletion) included in certain expense captions presented on the 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 may be applied either (1) prospectively to financial statements issued for reporting periods after the effective date of this ASU or (2) retrospectively to all prior periods presented in the financial statements. We are currently evaluating the impact this ASU will have on our disclosures.

SEC Release No. 33-11275, The Enhancement and Standardization of Climate-Related Disclosures for Investors
In March 2024, the SEC adopted rules under SEC Release No. 33-11275, The Enhancement and Standardization of Climate-Related Disclosures for Investors, which requires registrants to provide certain climate-related information in their annual reports. As part of the disclosures, material impacts from severe weather events and other natural conditions will be required in the audited financial statements. In April 2024, the SEC voluntarily stayed the rules pending judicial review. Pending the results of
the judicial review, the disclosure requirements are effective for the Partnership’s Annual Report on Form 10-K for the fiscal year ending December 31, 2025. We are evaluating the impact these rules will have on our disclosures and monitoring the status of the judicial review.
ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures
In November 2023, the FASB issued an ASU to update reportable segment disclosure requirements primarily by requiring enhanced disclosures about significant segment expenses. This ASU is effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The amendments should be applied retrospectively to all prior periods presented in the financial statements. This standard will have no impact on the Partnership’s financial statements, but will result in additional disclosure.
v3.24.3
Business Combinations and Asset Acquisitions
 9 Months Ended
Sep. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]  
Mergers, Acquisitions and Dispositions Disclosures Acquisitions and Other Transactions
BANGL, LLC Acquisition
On July 31, 2024, MPLX exercised its right of first offer under the BANGL, LLC joint venture agreement to purchase an additional 20 percent ownership interest in BANGL, LLC, for $210 million cash, increasing total ownership interest to 45 percent (the “BANGL Transaction”). BANGL is a natural gas liquids pipeline system connecting the Delaware and Midland basins to the fractionation market in Sweeny, Texas. The purchase price of the additional 20 percent ownership interest in BANGL, LLC exceeded our portion of the underlying net assets of the joint venture by approximately $156 million. This basis difference is being amortized into net income over the remaining estimated useful lives of the underlying net assets. Following the BANGL Transaction, our investment in BANGL, LLC continues to be accounted for as an equity method investment.
Whistler Joint Venture Transaction
On May 29, 2024, MPLX and its joint venture partner contributed their respective membership interest in Whistler Pipeline, LLC to a newly formed joint venture, WPC Parent, LLC, and issued a 19 percent voting interest in WPC Parent, LLC to an affiliate of Enbridge Inc. in exchange for the contribution of cash and the Rio Bravo Pipeline project. As a result of the transaction, MPLX’s voting interest in the joint venture was reduced from 37.5 percent to 30.4 percent. MPLX recognized a gain of $151 million and received a cash distribution of $134 million, recorded as a return of capital, related to the dilution of the ownership interest. The gain is included in Income from equity method investments on the accompanying consolidated statements of income and the return of capital is included in Investments - redemptions, repayments, return of capital and sales proceeds within the investing section of the accompanying consolidated statements of cash flows.
Utica Midstream Acquisition
On March 22, 2024, MPLX used $625 million of cash on hand to purchase additional ownership interest in existing joint ventures and gathering assets (the “Utica Midstream Acquisition”), which will enhance our position in the Utica basin. Prior to the acquisition, we owned an indirect interest in Ohio Gathering Company L.L.C. (“OGC”) and a direct interest in Ohio Condensate Company L.L.C. (“OCC”) and now own a combined 73 percent interest in OGC, a 100 percent interest in OCC, and a 100 percent interest in a dry gas gathering system in the Utica basin, including 53 miles of gathering pipeline and three dehydration units with a combined capacity of approximately 620 MMcf/d. OGC continues to be accounted for as an equity method investment, as MPLX did not obtain control of OGC as a result of the transaction. The acquisition date fair value of our investment in OGC exceeded our portion of the underlying net assets of the joint venture by approximately $86 million. This basis difference is being amortized into net income over the remaining estimated useful lives of the underlying net assets. OCC was previously accounted for as an equity method investment, and it is now reflected as a consolidated subsidiary within our consolidated financial results. The results for the acquired business are reported within our G&P segment.
The Utica Midstream Acquisition was accounted for as a business combination requiring all the acquired assets and liabilities to be remeasured to fair value resulting in a consolidated fair value of net assets and liabilities of $625 million. The fair value includes $518 million related to acquired interests in the joint ventures and the remaining balance related to other acquired assets and liabilities. The revaluation of MPLX’s existing 62 percent equity method investment in OCC resulted in a $20 million gain, which is included in Other income within the accompanying consolidated statements of income. The fair value of equity method investments was based on a discounted cash flow model.
v3.24.3
Investments and Noncontrolling Interests
 9 Months Ended
Sep. 30, 2024
Equity Method Investments and Joint Ventures [Abstract]  
Investments and Noncontrolling Interests Investments and Noncontrolling Interests
The following table presents MPLX’s equity method investments at the dates indicated:
Ownership as ofCarrying value at
September 30,September 30,December 31,
(In millions, except ownership percentages)VIE202420242023
L&S
BANGL, LLC(1)
45%$275 $63 
Illinois Extension Pipeline Company, L.L.C.35%231 228 
LOOP LLC41%313 314 
MarEn Bakken Company LLC(2)
25%530 449 
WPC Parent, LLC(3)
30%206 214 
Other(4)
X593 564 
Total L&S2,148 1,832 
G&P
MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.CX67%335 336 
MarkWest Utica EMG, L.L.C.X59%717 676 
Ohio Gathering Company L.L.C.(5)
X35%488 — 
Sherwood Midstream LLCX50%492 500 
Other(4)
X378 399 
Total G&P2,410 1,911 
Total$4,558 $3,743 
(1)    In July 2024, we purchased an additional 20 percent ownership interest in BANGL, LLC, increasing our ownership interest to 45 percent, as discussed in Note 3.
(2)    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”).    
(3)    Reflects the dilution of MPLX’s ownership interest in Whistler Pipeline, LLC and the formation of a new entity, WPC Parent, LLC, as discussed in Note 3. The carrying value at September 30, 2024 represents our ownership in WPC Parent, LLC, and the carrying value at December 31, 2023 represents our ownership interest in Whistler Pipeline, LLC.
(4)    Some investments included within Other have also been deemed to be VIEs.
(5)    We acquired a 36 percent direct interest in OGC in the Utica Midstream Acquisition discussed in Note 3. We also hold a 38 percent indirect interest in OGC 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, 2024 and September 30, 2023. See Note 16 for information on our guarantees related to equity method investees.
v3.24.3
Related Party Agreements and Transactions
 9 Months Ended
Sep. 30, 2024
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.
MPLX has various long-term, fee-based commercial agreements with MPC. Under these agreements, MPLX provides transportation, gathering, terminal, fuels distribution, marketing, storage, management, operational and other services to MPC. MPC has committed to provide MPLX with minimum quarterly throughput volumes on crude oil and refined products and other fees for storage capacity; operating and management fees; and reimbursements for certain direct and indirect costs. MPC has also committed to provide a fixed fee for 100 percent of available capacity for boats, barges and third-party chartered equipment under the marine transportation service agreements. MPLX also has a keep-whole commodity agreement with MPC under which MPC pays us a processing fee for NGLs related to keep-whole agreements and we pay MPC a marketing fee in exchange for assuming the commodity risk. In addition, MPLX has obligations to MPC for services provided to MPLX by MPC under omnibus and employee services type agreements as well as various other agreements.
During the second quarter of 2024, MPC exercised a five-year renewal option pursuant to the terms of an existing terminal services agreement with an initial term ending on March 31, 2026, with the term of the agreement now extending to 2031.The agreement includes both revenue and lease components. At the time of renewal, minimum future rental payments on non-cancellable operating leases increased $696 million, and minimum future undiscounted lease payment receipts under sales-type leases increased $90 million. Future performance obligations for the revenue component of the agreement include variable consideration that is not required to be estimated.
Related Party Loan
MPLX is party to a loan agreement (the “MPC Loan Agreement”) with MPC. Under the terms of the MPC Loan Agreement, MPC extends loans to MPLX on a revolving basis as requested by MPLX and as agreed to by MPC. The borrowing capacity of the MPC Loan Agreement is $1.5 billion aggregate principal amount of all loans outstanding at any one time. The MPC Loan Agreement was renewed on July 31, 2024 and is now scheduled to expire, and borrowings under the loan agreement are scheduled to mature and become due and payable, on July 31, 2029, provided that MPC may demand payment of all or any portion of the outstanding principal amount of the loan, together with all accrued and unpaid interest and other amounts (if any), at any time prior to maturity. Borrowings under the MPC Loan Agreement bear interest at one-month term SOFR adjusted upward by 0.10 percent plus 1.25 percent or such lower rate as would be applicable to such loans under the MPLX Credit Agreement as discussed in Note 12.
There was no activity on the MPC Loan Agreement for the nine months ended September 30, 2024.
Related Party Revenue
Related party sales to MPC primarily consist of crude oil and refined products pipeline services based on tariff or contracted rates; storage, terminal and fuels distribution services based on contracted rates; and marine transportation services. Related party sales to MPC also consist of revenue related to volume deficiency credits.
MPLX also has operating agreements with MPC under which it receives a fee for operating MPC’s retained pipeline assets and a fixed annual fee for providing oversight and management services required to run the marine business. MPLX also receives management fee revenue for engineering, construction and administrative services for operating certain of its equity method investments. Amounts earned under these agreements are classified as Other income - related parties in the Consolidated Statements of Income.
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, 2024, these sales totaled $177 million and $561 million, respectively. For the three and nine months ended September 30, 2023, these sales totaled $192 million and $540 million, respectively.
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”) and for certain employee services provided to MPLX under employee services agreements (“ESA charges”). 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. 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, 2024, General and administrative expenses incurred from MPC totaled $73 million and $217 million, respectively. For the three and nine months ended September 30, 2023, General and administrative expenses incurred from MPC totaled $72 million and $197 million, respectively.
Some charges incurred under the omnibus, employee service and co-location agreements are related to engineering and construction 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, 2024, these charges totaled $44 million and $124 million, respectively. For the three and nine months ended September 30, 2023, these charges totaled $28 million and $56 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. If MPC fails to meet its minimum committed volumes, MPC will pay MPLX a deficiency payment based on the terms of the applicable agreement. The deficiency amounts received under these agreements (excluding payments received under agreements classified as sales-type leases) are recorded as Current liabilities - related parties. In many cases, MPC may then apply the amount of any such deficiency payments as a credit for volumes in excess of its minimum volume commitment in future periods under the terms of the applicable agreements. MPLX recognizes related party revenues for the deficiency payments when credits are used for volumes in excess of minimum quarterly volume commitments, where it is probable the customer will not use the credit in future periods or upon the expiration of the credits. The use or expiration of the credits is a decrease in
Current liabilities - related parties. Deficiency payments under agreements that have been classified as sales-type leases are recorded as a reduction against the corresponding lease receivable. In addition, capital projects MPLX undertakes at the request of MPC are reimbursed in cash and recognized as revenue over the remaining term of the applicable agreements or in some cases, as a contribution from MPC.
(In millions)September 30,
2024		December 31,
2023
Current assets - related parties
Receivables$625 $587 
Lease receivables203 149 
Prepaid14 5 
Other— 7 
Total842 748 
Noncurrent assets - related parties
Long-term lease receivables711 789 
Right of use assets226 227 
Unguaranteed residual asset172 126 
Long-term receivables26 19 
Total1,135 1,161 
Current liabilities - related parties
MPC Loan Agreement and other payables(1)
264 278 
Deferred revenue89 81 
Operating lease liabilities1 1 
Total354 360 
Long-term liabilities - related parties
Long-term operating lease liabilities225 226 
Long-term deferred revenue95 99 
Total$320 $325 
(1)    There were no borrowings outstanding on the MPC Loan Agreement as of September 30, 2024 or December 31, 2023.
v3.24.3
Equity
 9 Months Ended
Sep. 30, 2024
Equity [Abstract]  
Equity Equity
The changes in the number of common units during the nine months ended September 30, 2024 are summarized below:
(In units)Common Units
Balance at December 31, 20231,003,498,875 
Unit-based compensation awards141,985 
Conversion of Series A preferred units21,078,998 
Units redeemed in unit repurchase program(5,473,621)
Balance at September 30, 20241,019,246,237 
Unit Repurchase Program
On August 2, 2022, we announced the board authorization for the repurchase of up to $1 billion of MPLX common units held by the public. This unit repurchase authorization has no expiration date. We may utilize various methods to effect the repurchases, which could include open market repurchases, negotiated block transactions, accelerated unit repurchases, tender offers or open market solicitations for units, some of which may be effected through Rule 10b5-1 plans. The timing and amount of future repurchases, if any, will depend upon several factors, including market and business conditions, and such repurchases may be suspended, discontinued or restarted at any time.
Total unit repurchases were as follows for the respective periods:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions, except per unit data)2024202320242023
Number of common units repurchased1.8 — 5.5 — 
Cash paid for common units repurchased(1)
$76 $— $226 $— 
Average cost per unit(1)
$42.89 $— $41.32 $— 
(1)    Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.
As of September 30, 2024, we had $620 million remaining under the unit repurchase authorization.
Series A Redeemable Preferred Unit Conversions
During the nine months ended September 30, 2024, certain Series A preferred unitholders exercised their rights to convert their Series A preferred units into approximately 21 million common units. Approximately 6 million Series A preferred units remain outstanding as of September 30, 2024.
Redemption of the Series B Preferred Units
On February 15, 2023, MPLX exercised its right to redeem all 600,000 outstanding 6.875 percent Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the “Series B preferred units”). MPLX paid unitholders the Series B preferred unit redemption price of $1,000 per unit. MPLX made a final cash distribution of $21 million to Series B preferred unitholders on February 15, 2023, in conjunction with the redemption.
Distributions
On October 29, 2024, MPLX declared a cash distribution for the third quarter of 2024, totaling $974 million, or $0.9565 per common unit. This distribution will be paid on November 15, 2024 to common unitholders of record on November 8, 2024. This rate will also be received by Series A preferred unitholders.
Quarterly distributions for 2024 and 2023 are summarized below:
(Per common unit)20242023
March 31,$0.8500 $0.7750 
June 30,0.8500 0.7750 
September 30,$0.9565 $0.8500 
The allocation of total quarterly cash distributions to common and preferred unitholders is as follows for the three and nine months ended September 30, 2024 and September 30, 2023. Distributions, although earned, are not accrued until declared. MPLX’s distributions are declared subsequent to quarter end; therefore, the following table represents total cash distributions applicable to the period in which the distributions were earned.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2024202320242023
Common and preferred unit distributions:
Common unitholders, includes common units of general partner$974 $851 $2,706 $2,403 
Series A preferred unit distributions6 25 21 71 
Series B preferred unit distributions(1)
— — — 5 
Total cash distributions declared$980 $876 $2,727 $2,479 
(1)    The nine months ended September 30, 2023 includes the portion of the $21 million distribution paid to the Series B preferred unitholders on February 15, 2023 that was earned during the period prior to redemption.
v3.24.3
Net Income Per Limited Partner Unit
 9 Months Ended
Sep. 30, 2024
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, 2024 and September 30, 2023, MPLX had participating securities consisting of common units, certain equity-based compensation awards, Series A preferred units, and Series B preferred units and also had dilutive potential common units consisting of certain equity-based compensation awards. Potential common units omitted from the diluted earnings per unit calculation for the three and nine months ended September 30, 2024 and September 30, 2023 were less than 1 million.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions, except per unit data)2024202320242023
Net income attributable to MPLX LP(1):
$1,037 $918 $3,218 $2,794 
Less: Distributions declared on Series A preferred units6 25 21 71 
Distributions declared on Series B preferred units— — — 5 
Undistributed earnings allocated to participating securities— 1 7 9 
Impact of redemption of Series B preferred units— — — 5 
Net Income available to common unitholders$1,031 $892 $3,190 $2,704 
Weighted average units outstanding:
Basic1,020 1,001 1,016 1,001 
Diluted1,020 1,001 1,016 1,001 
Net income attributable to MPLX LP per limited partner unit:
Basic$1.01 $0.89 $3.14 $2.70 
Diluted$1.01 $0.89 $3.14 $2.70 
(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.
v3.24.3
Segment Information
 9 Months Ended
Sep. 30, 2024
Segment Reporting [Abstract]  
Segment Reporting Disclosure 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 type of service basis. MPLX has two reportable segments: L&S and G&P. Each of these segments is organized and managed based upon the nature of the products and services it offers.
•L&S – 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.
•G&P – gathers, processes and transports natural gas; and transports, fractionates, stores and markets NGLs.
Our CODM evaluates the performance of our segments using Segment Adjusted EBITDA. Amounts included in net income and excluded from Segment Adjusted EBITDA include: (i) depreciation and amortization; (ii) net interest and other financial costs; (iii) income/(loss) from equity method investments; (iv) distributions and adjustments related to equity method investments; (v) impairment expense; (vi) noncontrolling interests; and (vii) other adjustments, as applicable. These items are either: (i) believed to be non-recurring in nature; (ii) not believed to be allocable or controlled by the segment; or (iii) are not tied to the operational performance of the segment. Assets by segment are not a measure used to assess the performance of the Partnership by our CODM and thus are not reported in our disclosures.
The tables below present information about revenues and other income, Segment Adjusted EBITDA, capital expenditures and investments in unconsolidated affiliates for our reportable segments:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2024202320242023
L&S
Service revenue$1,158 $1,130 $3,367 $3,223 
Rental income223 216 666 638 
Product related revenue5 6 14 14 
Sales-type lease revenue118 129 359 379 
Income from equity method investments80 95 429 248 
Other income33 15 113 47 
Total segment revenues and other income(1)
1,617 1,591 4,948 4,549 
Segment Adjusted EBITDA(2)
1,157 1,091 3,384 3,139 
Capital expenditures112 73 299 251 
Investments in unconsolidated affiliates(3)
10 7 103 23 
G&P
Service revenue617 549 1,785 1,620 
Rental income56 52 165 155 
Product related revenue565 598 1,606 1,629 
Sales-type lease revenue 34 34 102 101 
Income from equity method investments69 64 202 190 
Other income14 24 62 71 
Total segment revenues and other income(1)
1,355 1,321 3,922 3,766 
Segment Adjusted EBITDA(2)
557 505 1,618 1,507 
Capital expenditures189 151 421 417 
Investments in unconsolidated affiliates$22 $6 $83 $67 
(1)    Within the total segment revenues and other income amounts presented above, third party revenues for the L&S segment were $196 million and $779 million for the three and nine months ended September 30, 2024, respectively, and $207 million and $564 million for the three and nine months ended September 30, 2023, respectively. Third party revenues for the G&P segment were $1,285 million and $3,705 million for the three and nine months ended September 30, 2024, respectively, and $1,248 million and $3,553 million for the three and nine months ended September 30, 2023, respectively.
(2)    See below for the reconciliation from Segment Adjusted EBITDA to Net income.
(3)    The nine months ended September 30, 2024 includes a contribution of $92 million to Dakota Access to fund our share of a debt repayment by the joint venture.
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)2024202320242023
Reconciliation to Net income:
L&S Segment Adjusted EBITDA$1,157 $1,091 $3,384 $3,139 
G&P Segment Adjusted EBITDA557 505 1,618 1,507 
Total reportable segments1,714 1,596 5,002 4,646 
Depreciation and amortization(1)
(322)(301)(959)(907)
Net interest and other financial costs(226)(225)(692)(701)
Income from equity method investments149 159 631 438 
Distributions/adjustments related to equity method investments(253)(208)(671)(551)
Adjusted EBITDA attributable to noncontrolling interests11 11 33 31 
Garyville incident response costs(2)
— (63)— (63)
Other(3)
(26)(41)(96)(71)
Net income$1,047 $928 $3,248 $2,822 
(1)    Depreciation and amortization attributable to L&S was $132 million and $393 million for the three and nine months ended September 30, 2024, respectively, and $130 million and $399 million for the three and nine months ended September 30, 2023, respectively. Depreciation and amortization attributable to G&P was $190 million and $566 million for the three and nine months ended September 30, 2024, respectively, and $171 million and $508 million for the three and nine months ended September 30, 2023, respectively.
(2)    In August 2023, a naphtha release and resulting fire occurred at our Garyville Tank Farm resulting in the loss of four storage tanks with a combined shell capacity of 894 thousand barrels. We incurred $63 million of incident response costs during the three and nine months ended September 30, 2023.
(3)    Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.
v3.24.3
Property, Plant and Equipment
 9 Months Ended
Sep. 30, 2024
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, 2024December 31, 2023
(In millions)Gross PP&EAccumulated DepreciationNet PP&EGross PP&EAccumulated DepreciationNet PP&E
L&S $13,037 $4,421 $8,616 $12,779 $4,037 $8,742 
G&P 15,087 4,550 10,537 14,606 4,084 10,522 
Total$28,124 $8,971 $19,153 $27,385 $8,121 $19,264 
v3.24.3
Fair Value Measurements
 9 Months Ended
Sep. 30, 2024
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 financial instruments carried at fair value on a recurring basis as of September 30, 2024 and December 31, 2023 by fair value hierarchy level.
September 30, 2024December 31, 2023
(In millions)AssetLiabilityAssetLiability
Commodity contracts (Level 2)
Other current assets / Other current liabilities$1 $— $— $— 
Embedded derivatives in commodity contracts (Level 3)
Other current assets / Other current liabilities— 10 — 11 
Other noncurrent assets / Other long-term liabilities— 59 — 50 
Total carrying value in Consolidated Balance Sheets$1 $69 $— $61 
Level 2 instruments include over-the-counter fixed swaps to mitigate the price risk from our sales of propane under certain percent-of-proceeds and keep-whole arrangements. The swap valuations are based on observable inputs in the form of forward prices based on Mont Belvieu propane forward spot prices and contain no significant unobservable inputs.
Level 3 instruments relate to an embedded derivative liability for a natural gas purchase commitment embedded in a keep-whole processing agreement. The fair value calculation for these Level 3 instruments used significant unobservable inputs including: (1) NGL prices interpolated and extrapolated due to inactive markets ranging from $0.67 to $1.45 per gallon with a weighted average
of $0.85 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)2024202320242023
Beginning balance $(69)$(53)$(61)$(61)
Unrealized and realized (loss)/gain included in Net Income(1)
(3)(10)(18)(7)
Settlements3 3 10 8 
Ending balance$(69)$(60)$(69)$(60)
The amount of total loss for the period included in earnings attributable to the change in unrealized (loss)/gain relating to liabilities still held at end of period$(3)$(9)$(15)$(6)
(1)    (Loss)/gain on derivatives embedded in commodity contracts are recorded in Purchased product costs in the Consolidated Statements of Income.
Fair Values – Non-recurring
Non-recurring fair value measurements and disclosures in 2024 relate to acquisitions and other transactions as discussed in Note 3.
Fair Values – Reported
We believe the carrying value of our other financial instruments, including cash and cash equivalents, receivables, receivables from related parties, lease receivables, lease receivables from related parties, accounts payable, and payables to related parties, approximate fair value. MPLX’s fair value assessment incorporates a variety of considerations, including the duration of the instruments, MPC’s investment-grade credit rating, and the historical incurrence of and expected future insignificance of bad debt expense, which includes an evaluation of counterparty credit risk. The recorded value of the amounts outstanding under the bank revolving credit facility, if any, approximates fair value due to the variable interest rate that approximates current market rates. Derivative instruments are recorded at fair value, based on available market information (see Note 11).
The fair value of MPLX’s debt is estimated based on prices from recent trade activity and is categorized in Level 3 of the fair value hierarchy. The following table summarizes the fair value and carrying value of our third-party debt, excluding finance leases and unamortized debt issuance costs:
September 30, 2024December 31, 2023
(In millions)Fair ValueCarrying ValueFair ValueCarrying Value
Outstanding debt(1)
$21,494 $22,209 $19,377 $20,547 
(1)    Any amounts outstanding under the MPC Loan Agreement are not included in the table above, as the carrying value approximates fair value. This balance is reflected in Current liabilities - related parties in the Consolidated Balance Sheets.
Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring
Level 2 instruments include over-the-counter fixed swaps to mitigate the price risk from our sales of propane under certain percent-of-proceeds and keep-whole arrangements. The swap valuations are based on observable inputs in the form of forward prices based on Mont Belvieu propane forward spot prices and contain no significant unobservable inputs.
Level 3 instruments relate to an embedded derivative liability for a natural gas purchase commitment embedded in a keep-whole processing agreement. The fair value calculation for these Level 3 instruments used significant unobservable inputs including: (1) NGL prices interpolated and extrapolated due to inactive markets ranging from $0.67 to $1.45 per gallon with a weighted average
of $0.85 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.
v3.24.3
Derivative Financial Instruments
 9 Months Ended
Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Derivative Disclosure Derivatives
As of September 30, 2024, MPLX had the following outstanding commodity contracts that were executed to manage the price risk associated with sales of propane under certain percent-of-proceeds and keep-whole arrangements during 2024. Any gains or losses on these contracts are recorded in earnings through Product sales in the Consolidated Statements of Income:
Derivative contracts not designated as hedging instrumentsFinancial PositionNotional Quantity
Propane (gal)Short14,427,000 
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. As of September 30, 2024 and December 31, 2023, the estimated fair value of this contract was a liability of $69 million and $61 million, respectively.
Certain derivative positions are subject to master netting agreements; therefore, MPLX has elected to offset derivative assets and liabilities that are legally permissible to be offset. As of September 30, 2024 and December 31, 2023, there were no derivative assets or liabilities that were offset in the Consolidated Balance Sheets.
We make a distinction between realized or unrealized gains and losses on derivatives. During the period when a derivative contract is outstanding, changes in the fair value of the derivative are recorded as an unrealized gain or loss. When a derivative contract matures or is settled, the previously recorded unrealized gain or loss is reversed, and the realized gain or loss of the contract is recorded. 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)2024202320242023
Product sales:
Realized gain$1 $3 $1 $3 
Unrealized gain/(loss)3 (8)1 2 
Product sales derivative gain/(loss)4 (5)2 5 
Purchased product costs:
Realized loss(3)(3)(10)(8)
Unrealized (loss)/gain— (7)(8)1 
Purchased product cost derivative loss(3)(10)(18)(7)
Total derivative gain/(loss) included in Net income$1 $(15)$(16)$(2)
v3.24.3
Debt
 9 Months Ended
Sep. 30, 2024
Debt Disclosure [Abstract]  
Debt Debt
MPLX’s outstanding borrowings consist of the following:
(In millions)September 30,
2024		December 31,
2023
MPLX LP:
MPLX Credit Agreement$— $— 
Fixed rate senior notes22,307 20,657 
Consolidated subsidiaries:
MarkWest12 12 
ANDX31 31 
Finance lease obligations6 6 
Total22,356 20,706 
Unamortized debt issuance costs(129)(122)
Unamortized discount(141)(153)
Amounts due within one year(2,836)(1,135)
Total long-term debt due after one year$19,250 $19,296 
Credit Agreement
MPLX’s credit agreement (the “MPLX Credit Agreement”) matures in July 2027 and, among other things, provides for a $2 billion unsecured revolving credit facility and letter of credit issuing capacity under the facility of up to $150 million. Letter of credit issuing capacity is included in, not in addition to, the $2 billion borrowing capacity. Borrowings under the MPLX Credit Agreement bear interest, at MPLX’s election, at either the Adjusted Term SOFR or the Alternate Base Rate, both as defined in the MPLX Credit Agreement, plus an applicable margin.
There was no activity on the MPLX Credit Agreement during the nine months ended September 30, 2024.
Fixed Rate Senior Notes
MPLX’s senior notes, including those issued by consolidated subsidiaries, consist of various series of senior notes maturing between 2024 and 2058 with interest rates ranging from 1.750 percent to 5.650 percent. Interest on each series of notes is payable semi-annually in arrears on various dates depending on the series of the notes.
On May 20, 2024, MPLX issued $1.65 billion aggregate principal amount of 5.50 percent senior notes due 2034 (the “2034 Senior Notes”) in an underwritten public offering. The 2034 Senior Notes were offered at a price to the public of 98.778 percent of par, with interest payable semi-annually in arrears, commencing on December 1, 2024. MPLX intends to use the net proceeds from the issuance of the 2034 Senior Notes to repay, redeem, or otherwise retire some or all of (i) MPLX’s outstanding $1,149 million aggregate principal amount of 4.875 percent senior notes due December 2024, (ii) MarkWest’s outstanding $1 million aggregate principal amount of 4.875 percent senior notes due December 2024 and (iii) MPLX’s outstanding $500 million aggregate principal amount of 4.000 percent senior notes due February 2025, and in the interim may use such net proceeds for general partnership purposes.
v3.24.3
Interest and Other Financial Costs
 9 Months Ended
Sep. 30, 2024
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)2024202320242023
Interest expense$251 $227 $717 $684 
Other financial costs15 14 57 55 
Interest income(35)(12)(68)(27)
Capitalized interest(5)(4)(14)(11)
Net interest and other financial costs$226 $225 $692 $701 
v3.24.3
Revenue
 9 Months Ended
Sep. 30, 2024
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, 2024 and September 30, 2023:
Three Months Ended September 30, 2024
(In millions)L&SG&PTotal
Revenues and other income:
Service revenue$101 $608 $709 
Service revenue - related parties1,057 9 1,066 
Service revenue - product related— 86 86 
Product sales1 432 433 
Product sales - related parties4 47 51 
Total revenues from contracts with customers$1,163 $1,182 2,345 
Non-ASC 606 revenue(1)
627 
Total revenues and other income$2,972 
Three Months Ended September 30, 2023
(In millions)L&SG&PTotal
Revenues and other income:
Service revenue$97 $544 $641 
Service revenue - related parties1,033 5 1,038 
Service revenue - product related— 75 75 
Product sales2 476 478 
Product sales - related parties4 47 51 
Total revenues from contracts with customers$1,136 $1,147 2,283 
Non-ASC 606 revenue(1)
629 
Total revenues and other income$2,912 
Nine Months Ended September 30, 2024
(In millions)L&SG&PTotal
Revenues and other income:
Service revenue$286 $1,764 $2,050 
Service revenue - related parties3,081 21 3,102 
Service revenue - product related— 265 265 
Product sales4 1,187 1,191 
Product sales - related parties10 154 164 
Total revenues from contracts with customers$3,381 $3,391 6,772 
Non-ASC 606 revenue(1)
2,098 
Total revenues and other income$8,870 
Nine Months Ended September 30, 2023
(In millions)L&SG&PTotal
Revenues and other income:
Service revenue$272 $1,609 $1,881 
Service revenue - related parties2,951 11 2,962 
Service revenue - product related— 214 214 
Product sales4 1,270 1,274 
Product sales - related parties10 145 155 
Total revenues from contracts with customers$3,237 $3,249 6,486 
Non-ASC 606 revenue(1)
1,829 
Total revenues and other income$8,315 
(1)    Non-ASC 606 Revenue includes rental income, sales-type lease revenue, income from equity method investments, and other income.
Contract Balances
Our receivables are primarily associated with customer contracts. Payment terms vary by product or service type; however, the period between invoicing and payment is not significant. Included within the receivables are balances related to commodity sales on behalf of our producer customers, for which we remit the net sales price back to the producer customers upon completion of the sale.
Under certain of our contracts, we recognize revenues in excess of billings which we present as contract assets. Contract assets typically relate to deficiency payments related to minimum volume commitments and aid in construction agreements where the revenue recognized and MPLX’s rights to consideration for work completed exceeds the amount billed to the customer. Contract assets are included in Other current assets and Other noncurrent assets on the Consolidated Balance Sheets.
Under certain of our contracts, we receive payments in advance of satisfying our performance obligations, which are recorded as contract liabilities. Contract liabilities, which we present as Deferred revenue and Long-term deferred revenue, typically relate to advance payments for aid in construction agreements and deferred customer credits associated with makeup rights and minimum volume commitments. Related to minimum volume commitments, breakage is estimated and recognized into service revenue in instances where it is probable the customer will not use the credit in future periods. We classify contract liabilities as current or long-term based on the timing of when we expect to recognize revenue.
The tables below reflect the changes in ASC 606 contract balances for the nine months ended September 30, 2024 and September 30, 2023:
(In millions)Balance at December 31, 2023Additions/ (Deletions)
Revenue Recognized(1)
Balance at September 30, 2024
Contract assets$3 $— $(1)$2 
Long-term contract assets1 (1)— — 
Deferred revenue59 65 (42)82 
Deferred revenue - related parties47 56 (50)53 
Long-term deferred revenue344 (22)— 322 
Long-term deferred revenue - related parties$29 $5 $— $34 
(In millions)Balance at December 31, 2022Additions/ (Deletions)
Revenue Recognized(1)
Balance at September 30, 2023
Contract assets$21 $(19)$— $2 
Long-term contract assets1 — — 1 
Deferred revenue57 24 (31)50 
Deferred revenue - related parties63 63 (72)54 
Long-term deferred revenue216 76 — 292 
Long-term deferred revenue - related parties25 5 — 30 
Long-term contract liabilities$2 $(2)$— $— 
(1)    No significant revenue was recognized related to past performance obligations in the current periods.
Remaining Performance Obligations
The table below includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially unsatisfied) as of September 30, 2024. The amounts presented below are generally limited to fixed consideration from contracts with customers that contain minimum volume commitments.
A significant portion of our future contracted revenue is excluded from the amounts presented below in accordance with ASC 606. Variable consideration that is constrained or not required to be estimated as it reflects our efforts to perform is excluded from this disclosure. Additionally, we do not disclose information on the future performance obligations for any contract with an original expected duration of one year or less, or that are terminable by our customer with little or no termination penalties. Potential future performance obligations related to renewals that have not yet been exercised or are not certain of exercise are excluded from the amounts presented below. Revenues classified as Rental income and Sales-type lease revenue are also excluded from this table.
(In billions)
2024$0.6 
20252.1 
20261.9 
20271.8 
20280.6 
2029 and thereafter0.8 
Total estimated revenue on remaining performance obligations$7.8 
As of September 30, 2024, unsatisfied performance obligations included in the Consolidated Balance Sheets are $491 million and will be recognized as revenue as the obligations are satisfied, which is generally expected to occur over the next 20 years. A portion of this amount is not disclosed in the table above as it is deemed variable consideration due to volume variability.
v3.24.3
Supplemental Cash Flow Information
 9 Months Ended
Sep. 30, 2024
Supplemental Cash Flow Elements [Abstract]  
Supplemental Cash Flow Information Supplemental Cash Flow Information
 Nine Months Ended 
September 30,
(In millions)20242023
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)$724 $724 
Income taxes paid2 4 
Cash paid for amounts included in the measurement of lease liabilities:
Payments on operating leases53 53 
Net cash provided by financing activities included:
Principal payments under finance lease obligations1 1 
Non-cash investing and financing activities:
Net transfers of property, plant and equipment (to)/from materials and supplies inventory— 8 
Net transfers of property, plant and equipment to lease receivable108 86 
ROU assets obtained in exchange for new operating lease obligations$34 $19 
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)20242023
Additions to property, plant and equipment$748 $662 
(Decrease)/Increase in capital accruals(28)6 
Total capital expenditures$720 $668 
v3.24.3
Commitments and Contingencies
 9 Months Ended
Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies Commitments and Contingencies
MPLX is the subject of, or a party to, a number of pending or threatened legal actions, contingencies and commitments involving a variety of matters, including laws and regulations relating to the environment. Some of these matters are discussed below. For matters for which MPLX has not recorded a liability, MPLX is unable to estimate a range of possible loss because the issues involved have not been fully developed through pleadings, discovery or court proceedings. However, the ultimate resolution of some of these contingencies could, individually or in the aggregate, be material.
Environmental Matters
MPLX is subject to federal, state and local laws and regulations relating to the environment. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation of hazardous waste disposal sites. Penalties may be imposed for non-compliance.
Accrued liabilities for remediation totaled $15 million at September 30, 2024 and $19 million December 31, 2023. 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.
MPLX is involved in environmental enforcement matters arising in the ordinary course of business. While the outcome and impact to MPLX cannot be predicted with certainty, management believes the resolution of these environmental matters will not, individually or collectively, have a material adverse effect on its consolidated results of operations, financial position or cash flows.
Other Legal Proceedings
In July 2020, Tesoro High Plains Pipeline Company, LLC (“THPP”), a subsidiary of MPLX, received a Notification of Trespass Determination from the Bureau of Indian Affairs (“BIA”) relating to a portion of the Tesoro High Plains Pipeline that crosses the Fort Berthold Reservation in North Dakota. The notification demanded the immediate cessation of pipeline operations and assessed trespass damages of approximately $187 million. After subsequent appeal proceedings and in compliance with a new order issued by the BIA, in December 2020, THPP paid approximately $4 million in assessed trespass damages and ceased use of the portion of the pipeline that crosses the property at issue. In March 2021, the BIA issued an order purporting to vacate the BIA's prior orders related to THPP’s alleged trespass and direct the Regional Director of the BIA to reconsider the issue of THPP’s alleged trespass and issue a new order. In April 2021, THPP filed a lawsuit in the District of North Dakota against the United States of America, the U.S. Department of the Interior and the BIA (collectively, the “U.S. Government Parties”) challenging the March 2021 order purporting to vacate all previous orders related to THPP’s alleged trespass. On February 8, 2022, the U.S. Government Parties filed their answer and counterclaims to THPP’s suit claiming THPP is in continued trespass with respect to the pipeline and seeking disgorgement of pipeline profits from June 1, 2013 to present, removal of the pipeline
and remediation. On November 8, 2023, the District Court of North Dakota granted THPP’s motion to sever and stay the U.S. Government Parties’ counterclaims. The case will proceed on the merits of THPP’s challenge to the March 2021 order purporting to vacate all previous orders related to THPP’s alleged trespass. THPP continues not to operate that portion of the pipeline that crosses the property at issue.
MPLX is also a party to a number of other lawsuits and other proceedings arising in the ordinary course of business. While the ultimate outcome and impact to MPLX cannot be predicted with certainty, management believes the resolution of these other lawsuits and proceedings will not, individually or collectively, have a material adverse effect on its consolidated financial position, results of operations or cash flows.
Guarantees related to indebtedness of equity method investees
We hold a 9.19 percent indirect interest in Dakota Access, which owns and operates the Bakken Pipeline system. In 2020, the U.S. District Court for the District of Columbia (the “D.D.C.”) ordered the United States Army Corps of Engineers (“Army Corps”), which granted permits and an easement for the Bakken Pipeline system, to prepare an environmental impact statement (“EIS”) relating to an easement under Lake Oahe in North Dakota. The D.D.C. later vacated the easement. The Army Corps issued a draft EIS in September 2023 detailing various options for the easement going forward, including denying the easement, approving the easement with additional measures, rerouting the easement, or approving the easement with no changes. The Army Corps has not selected a preferred alternative, but will make a decision in its final review, after considering input from the public and other agencies. The pipeline remains operational while the Army Corps finalizes its decision which will follow the issuance of the final EIS. According to public statements from Army Corps officials, the EIS is now expected to be issued in 2025.
We have entered into a Contingent Equity Contribution Agreement whereby MPLX LP, along with the other joint venture owners in the Bakken Pipeline system, has agreed to make equity contributions to the joint venture upon certain events occurring to allow the entities that own and operate the Bakken Pipeline system to satisfy their senior note payment obligations. The senior notes were issued to repay amounts owed by the pipeline companies to fund the cost of construction of the Bakken Pipeline system.
If the vacatur of the easement results in a temporary shutdown of the pipeline, MPLX would have to contribute its 9.19 percent pro rata share of funds required to pay interest accruing on the notes and any portion of the principal that matures while the pipeline is shut down. MPLX also expects to contribute its 9.19 percent pro rata share of any costs to remediate any deficiencies to reinstate the easement and/or return the pipeline into operation. If the vacatur of the easement results in a permanent shutdown of the pipeline, MPLX would have to contribute its 9.19 percent pro rata share of the cost to redeem the bonds (including the one percent redemption premium required pursuant to the indenture governing the notes) and any accrued and unpaid interest. As of September 30, 2024, our maximum potential undiscounted payments under the Contingent Equity Contribution Agreement were approximately $78 million.
Other guarantees
MPLX’s maximum exposure to loss for WPC Parent, LLC includes an $82 million commitment to indemnify a joint venture member for our pro rata share of any payments made under a performance guarantee for construction of a pipeline by an equity method investee.
Contractual Commitments and Contingencies
From time to time and in the ordinary course of business, MPLX and its affiliates provide guarantees of MPLX’s subsidiaries payment and performance obligations in the G&P segment. Certain natural gas processing and gathering arrangements require MPLX to construct natural gas processing plants, natural gas gathering pipelines and NGL pipelines and contain certain fees and charges if specified construction milestones are not achieved for reasons other than force majeure. In certain cases, certain 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, 2024, management does not believe there are any indications that MPLX will not be able to meet the construction milestones, that force majeure does not apply or that such fees and charges will otherwise be triggered.
v3.24.3
Insider Trading Arrangements
 3 Months Ended
Sep. 30, 2024
Trading Arrangements, by Individual  
Material Terms of Trading Arrangement
During the quarter ended September 30, 2024, no director or officer (as defined in Rule 16a-1(f) promulgated under the Exchange Act) of MPLX adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement” (as each term is defined in Item 408 of Regulation S-K).
Rule 10b5-1 Arrangement Adopted false
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
v3.24.3
Description of the Business and Basis of Presentation Accounting Policies (Policies)
 9 Months Ended
Sep. 30, 2024
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, processing and transportation of natural gas; and the transportation, fractionation, storage and marketing of NGLs. MPLX’s principal executive office is located in Findlay, Ohio. MPLX was formed on March 27, 2012 as a Delaware limited partnership and completed its initial public offering on October 31, 2012.
MPLX’s business consists of two segments based on the nature of services it offers: Logistics and Storage (“L&S”), which relates primarily to crude oil, refined products, other hydrocarbon-based products and renewables; and Gathering and Processing (“G&P”), which relates primarily to natural gas and NGLs. See Note 8 for additional information regarding the operations and results of these segments.
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.
v3.24.3
Net Income Per Limited Partner Unit Accounting Policy (Policies)
 9 Months Ended
Sep. 30, 2024
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.
v3.24.3
Investments and Noncontrolling Interests (Tables)
 9 Months Ended
Sep. 30, 2024
Equity Method Investments and Joint Ventures [Abstract]  
Equity Method Investments
The following table presents MPLX’s equity method investments at the dates indicated:
Ownership as ofCarrying value at
September 30,September 30,December 31,
(In millions, except ownership percentages)VIE202420242023
L&S
BANGL, LLC(1)
45%$275 $63 
Illinois Extension Pipeline Company, L.L.C.35%231 228 
LOOP LLC41%313 314 
MarEn Bakken Company LLC(2)
25%530 449 
WPC Parent, LLC(3)
30%206 214 
Other(4)
X593 564 
Total L&S2,148 1,832 
G&P
MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.CX67%335 336 
MarkWest Utica EMG, L.L.C.X59%717 676 
Ohio Gathering Company L.L.C.(5)
X35%488 — 
Sherwood Midstream LLCX50%492 500 
Other(4)
X378 399 
Total G&P2,410 1,911 
Total$4,558 $3,743 
(1)    In July 2024, we purchased an additional 20 percent ownership interest in BANGL, LLC, increasing our ownership interest to 45 percent, as discussed in Note 3.
(2)    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”).    
(3)    Reflects the dilution of MPLX’s ownership interest in Whistler Pipeline, LLC and the formation of a new entity, WPC Parent, LLC, as discussed in Note 3. The carrying value at September 30, 2024 represents our ownership in WPC Parent, LLC, and the carrying value at December 31, 2023 represents our ownership interest in Whistler Pipeline, LLC.
(4)    Some investments included within Other have also been deemed to be VIEs.
(5)    We acquired a 36 percent direct interest in OGC in the Utica Midstream Acquisition discussed in Note 3. We also hold a 38 percent indirect interest in OGC through our ownership interest in MarkWest Utica EMG, L.L.C.
v3.24.3
Related Party Agreements and Transactions (Tables)
 9 Months Ended
Sep. 30, 2024
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. If MPC fails to meet its minimum committed volumes, MPC will pay MPLX a deficiency payment based on the terms of the applicable agreement. The deficiency amounts received under these agreements (excluding payments received under agreements classified as sales-type leases) are recorded as Current liabilities - related parties. In many cases, MPC may then apply the amount of any such deficiency payments as a credit for volumes in excess of its minimum volume commitment in future periods under the terms of the applicable agreements. MPLX recognizes related party revenues for the deficiency payments when credits are used for volumes in excess of minimum quarterly volume commitments, where it is probable the customer will not use the credit in future periods or upon the expiration of the credits. The use or expiration of the credits is a decrease in
Current liabilities - related parties. Deficiency payments under agreements that have been classified as sales-type leases are recorded as a reduction against the corresponding lease receivable. In addition, capital projects MPLX undertakes at the request of MPC are reimbursed in cash and recognized as revenue over the remaining term of the applicable agreements or in some cases, as a contribution from MPC.
(In millions)September 30,
2024		December 31,
2023
Current assets - related parties
Receivables$625 $587 
Lease receivables203 149 
Prepaid14 5 
Other— 7 
Total842 748 
Noncurrent assets - related parties
Long-term lease receivables711 789 
Right of use assets226 227 
Unguaranteed residual asset172 126 
Long-term receivables26 19 
Total1,135 1,161 
Current liabilities - related parties
MPC Loan Agreement and other payables(1)
264 278 
Deferred revenue89 81 
Operating lease liabilities1 1 
Total354 360 
Long-term liabilities - related parties
Long-term operating lease liabilities225 226 
Long-term deferred revenue95 99 
Total$320 $325 
(1)    There were no borrowings outstanding on the MPC Loan Agreement as of September 30, 2024 or December 31, 2023.
v3.24.3
Equity (Tables)
 9 Months Ended
Sep. 30, 2024
Equity [Abstract]  
Schedule of Stockholders Equity
The changes in the number of common units during the nine months ended September 30, 2024 are summarized below:
(In units)Common Units
Balance at December 31, 20231,003,498,875 
Unit-based compensation awards141,985 
Conversion of Series A preferred units21,078,998 
Units redeemed in unit repurchase program(5,473,621)
Balance at September 30, 20241,019,246,237 
Distributions Made to Limited Partner, by Distribution
The allocation of total quarterly cash distributions to common and preferred unitholders is as follows for the three and nine months ended September 30, 2024 and September 30, 2023. Distributions, although earned, are not accrued until declared. MPLX’s distributions are declared subsequent to quarter end; therefore, the following table represents total cash distributions applicable to the period in which the distributions were earned.
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2024202320242023
Common and preferred unit distributions:
Common unitholders, includes common units of general partner$974 $851 $2,706 $2,403 
Series A preferred unit distributions6 25 21 71 
Series B preferred unit distributions(1)
— — — 5 
Total cash distributions declared$980 $876 $2,727 $2,479 
(1)    The nine months ended September 30, 2023 includes the portion of the $21 million distribution paid to the Series B preferred unitholders on February 15, 2023 that was earned during the period prior to redemption.
v3.24.3
Net Income Per Limited Partner Unit (Tables)
 9 Months Ended
Sep. 30, 2024
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)2024202320242023
Net income attributable to MPLX LP(1):
$1,037 $918 $3,218 $2,794 
Less: Distributions declared on Series A preferred units6 25 21 71 
Distributions declared on Series B preferred units— — — 5 
Undistributed earnings allocated to participating securities— 1 7 9 
Impact of redemption of Series B preferred units— — — 5 
Net Income available to common unitholders$1,031 $892 $3,190 $2,704 
Weighted average units outstanding:
Basic1,020 1,001 1,016 1,001 
Diluted1,020 1,001 1,016 1,001 
Net income attributable to MPLX LP per limited partner unit:
Basic$1.01 $0.89 $3.14 $2.70 
Diluted$1.01 $0.89 $3.14 $2.70 
(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.
v3.24.3
Segment Information (Tables)
 9 Months Ended
Sep. 30, 2024
Segment Reporting [Abstract]  
Schedule of Segment Reporting Information, by Segment
The tables below present information about revenues and other income, Segment Adjusted EBITDA, capital expenditures and investments in unconsolidated affiliates for our reportable segments:
Three Months Ended 
September 30,		Nine Months Ended 
September 30,
(In millions)2024202320242023
L&S
Service revenue$1,158 $1,130 $3,367 $3,223 
Rental income223 216 666 638 
Product related revenue5 6 14 14 
Sales-type lease revenue118 129 359 379 
Income from equity method investments80 95 429 248 
Other income33 15 113 47 
Total segment revenues and other income(1)
1,617 1,591 4,948 4,549 
Segment Adjusted EBITDA(2)
1,157 1,091 3,384 3,139 
Capital expenditures112 73 299 251 
Investments in unconsolidated affiliates(3)
10 7 103 23 
G&P
Service revenue617 549 1,785 1,620 
Rental income56 52 165 155 
Product related revenue565 598 1,606 1,629 
Sales-type lease revenue 34 34 102 101 
Income from equity method investments69 64 202 190 
Other income14 24 62 71 
Total segment revenues and other income(1)
1,355 1,321 3,922 3,766 
Segment Adjusted EBITDA(2)
557 505 1,618 1,507 
Capital expenditures189 151 421 417 
Investments in unconsolidated affiliates$22 $6 $83 $67 
(1)    Within the total segment revenues and other income amounts presented above, third party revenues for the L&S segment were $196 million and $779 million for the three and nine months ended September 30, 2024, respectively, and $207 million and $564 million for the three and nine months ended September 30, 2023, respectively. Third party revenues for the G&P segment were $1,285 million and $3,705 million for the three and nine months ended September 30, 2024, respectively, and $1,248 million and $3,553 million for the three and nine months ended September 30, 2023, respectively.
(2)    See below for the reconciliation from Segment Adjusted EBITDA to Net income.
(3)    The nine months ended September 30, 2024 includes a contribution of $92 million to Dakota Access to fund our share of a debt repayment by the joint venture.
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)2024202320242023
Reconciliation to Net income:
L&S Segment Adjusted EBITDA$1,157 $1,091 $3,384 $3,139 
G&P Segment Adjusted EBITDA557 505 1,618 1,507 
Total reportable segments1,714 1,596 5,002 4,646 
Depreciation and amortization(1)
(322)(301)(959)(907)
Net interest and other financial costs(226)(225)(692)(701)
Income from equity method investments149 159 631 438 
Distributions/adjustments related to equity method investments(253)(208)(671)(551)
Adjusted EBITDA attributable to noncontrolling interests11 11 33 31 
Garyville incident response costs(2)
— (63)— (63)
Other(3)
(26)(41)(96)(71)
Net income$1,047 $928 $3,248 $2,822 
(1)    Depreciation and amortization attributable to L&S was $132 million and $393 million for the three and nine months ended September 30, 2024, respectively, and $130 million and $399 million for the three and nine months ended September 30, 2023, respectively. Depreciation and amortization attributable to G&P was $190 million and $566 million for the three and nine months ended September 30, 2024, respectively, and $171 million and $508 million for the three and nine months ended September 30, 2023, respectively.
(2)    In August 2023, a naphtha release and resulting fire occurred at our Garyville Tank Farm resulting in the loss of four storage tanks with a combined shell capacity of 894 thousand barrels. We incurred $63 million of incident response costs during the three and nine months ended September 30, 2023.
(3)    Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.
v3.24.3
Property, Plant and Equipment (Tables)
 9 Months Ended
Sep. 30, 2024
Property, Plant and Equipment [Abstract]  
Summary of Property, Plant and Equipment
Property, plant and equipment with associated accumulated depreciation is shown below:
September 30, 2024December 31, 2023
(In millions)Gross PP&EAccumulated DepreciationNet PP&EGross PP&EAccumulated DepreciationNet PP&E
L&S $13,037 $4,421 $8,616 $12,779 $4,037 $8,742 
G&P 15,087 4,550 10,537 14,606 4,084 10,522 
Total$28,124 $8,971 $19,153 $27,385 $8,121 $19,264 
v3.24.3
Fair Value Measurements (Tables)
 9 Months Ended
Sep. 30, 2024
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 financial instruments carried at fair value on a recurring basis as of September 30, 2024 and December 31, 2023 by fair value hierarchy level.
September 30, 2024December 31, 2023
(In millions)AssetLiabilityAssetLiability
Commodity contracts (Level 2)
Other current assets / Other current liabilities$1 $— $— $— 
Embedded derivatives in commodity contracts (Level 3)
Other current assets / Other current liabilities— 10 — 11 
Other noncurrent assets / Other long-term liabilities— 59 — 50 
Total carrying value in Consolidated Balance Sheets$1 $69 $— $61 
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)2024202320242023
Beginning balance $(69)$(53)$(61)$(61)
Unrealized and realized (loss)/gain included in Net Income(1)
(3)(10)(18)(7)
Settlements3 3 10 8 
Ending balance$(69)$(60)$(69)$(60)
The amount of total loss for the period included in earnings attributable to the change in unrealized (loss)/gain relating to liabilities still held at end of period$(3)$(9)$(15)$(6)
(1)    (Loss)/gain on derivatives embedded in commodity contracts are recorded in Purchased product costs in the Consolidated Statements of Income.
Fair Value Carrying Value by Balance Sheet Grouping 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, 2024December 31, 2023
(In millions)Fair ValueCarrying ValueFair ValueCarrying Value
Outstanding debt(1)
$21,494 $22,209 $19,377 $20,547 
(1)    Any amounts outstanding under the MPC Loan Agreement are not included in the table above, as the carrying value approximates fair value. This balance is reflected in Current liabilities - related parties in the Consolidated Balance Sheets.
v3.24.3
Derivative Financial Instruments (Tables)
 9 Months Ended
Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Notional Amounts of Outstanding Derivative Positions
As of September 30, 2024, MPLX had the following outstanding commodity contracts that were executed to manage the price risk associated with sales of propane under certain percent-of-proceeds and keep-whole arrangements during 2024. Any gains or losses on these contracts are recorded in earnings through Product sales in the Consolidated Statements of Income:
Derivative contracts not designated as hedging instrumentsFinancial PositionNotional Quantity
Propane (gal)Short14,427,000 
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)2024202320242023
Product sales:
Realized gain$1 $3 $1 $3 
Unrealized gain/(loss)3 (8)1 2 
Product sales derivative gain/(loss)4 (5)2 5 
Purchased product costs:
Realized loss(3)(3)(10)(8)
Unrealized (loss)/gain— (7)(8)1 
Purchased product cost derivative loss(3)(10)(18)(7)
Total derivative gain/(loss) included in Net income$1 $(15)$(16)$(2)
v3.24.3
Debt (Tables)
 9 Months Ended
Sep. 30, 2024
Debt Disclosure [Abstract]  
Schedule of Debt
MPLX’s outstanding borrowings consist of the following:
(In millions)September 30,
2024		December 31,
2023
MPLX LP:
MPLX Credit Agreement$— $— 
Fixed rate senior notes22,307 20,657 
Consolidated subsidiaries:
MarkWest12 12 
ANDX31 31 
Finance lease obligations6 6 
Total22,356 20,706 
Unamortized debt issuance costs(129)(122)
Unamortized discount(141)(153)
Amounts due within one year(2,836)(1,135)
Total long-term debt due after one year$19,250 $19,296 
v3.24.3
Interest and Other Financial Costs (Tables)
 9 Months Ended
Sep. 30, 2024
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)2024202320242023
Interest expense$251 $227 $717 $684 
Other financial costs15 14 57 55 
Interest income(35)(12)(68)(27)
Capitalized interest(5)(4)(14)(11)
Net interest and other financial costs$226 $225 $692 $701 
v3.24.3
Revenue (Tables)
 9 Months Ended
Sep. 30, 2024
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, 2024 and September 30, 2023:
Three Months Ended September 30, 2024
(In millions)L&SG&PTotal
Revenues and other income:
Service revenue$101 $608 $709 
Service revenue - related parties1,057 9 1,066 
Service revenue - product related— 86 86 
Product sales1 432 433 
Product sales - related parties4 47 51 
Total revenues from contracts with customers$1,163 $1,182 2,345 
Non-ASC 606 revenue(1)
627 
Total revenues and other income$2,972 
Three Months Ended September 30, 2023
(In millions)L&SG&PTotal
Revenues and other income:
Service revenue$97 $544 $641 
Service revenue - related parties1,033 5 1,038 
Service revenue - product related— 75 75 
Product sales2 476 478 
Product sales - related parties4 47 51 
Total revenues from contracts with customers$1,136 $1,147 2,283 
Non-ASC 606 revenue(1)
629 
Total revenues and other income$2,912 
Nine Months Ended September 30, 2024
(In millions)L&SG&PTotal
Revenues and other income:
Service revenue$286 $1,764 $2,050 
Service revenue - related parties3,081 21 3,102 
Service revenue - product related— 265 265 
Product sales4 1,187 1,191 
Product sales - related parties10 154 164 
Total revenues from contracts with customers$3,381 $3,391 6,772 
Non-ASC 606 revenue(1)
2,098 
Total revenues and other income$8,870 
Nine Months Ended September 30, 2023
(In millions)L&SG&PTotal
Revenues and other income:
Service revenue$272 $1,609 $1,881 
Service revenue - related parties2,951 11 2,962 
Service revenue - product related— 214 214 
Product sales4 1,270 1,274 
Product sales - related parties10 145 155 
Total revenues from contracts with customers$3,237 $3,249 6,486 
Non-ASC 606 revenue(1)
1,829 
Total revenues and other income$8,315 
(1)    Non-ASC 606 Revenue 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, 2024 and September 30, 2023:
(In millions)Balance at December 31, 2023Additions/ (Deletions)
Revenue Recognized(1)
Balance at September 30, 2024
Contract assets$3 $— $(1)$2 
Long-term contract assets1 (1)— — 
Deferred revenue59 65 (42)82 
Deferred revenue - related parties47 56 (50)53 
Long-term deferred revenue344 (22)— 322 
Long-term deferred revenue - related parties$29 $5 $— $34 
(In millions)Balance at December 31, 2022Additions/ (Deletions)
Revenue Recognized(1)
Balance at September 30, 2023
Contract assets$21 $(19)$— $2 
Long-term contract assets1 — — 1 
Deferred revenue57 24 (31)50 
Deferred revenue - related parties63 63 (72)54 
Long-term deferred revenue216 76 — 292 
Long-term deferred revenue - related parties25 5 — 30 
Long-term contract liabilities$2 $(2)$— $— 
(1)    No significant revenue was recognized related to past performance obligations in the current periods.
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, 2024. The amounts presented below are generally limited to fixed consideration from contracts with customers that contain minimum volume commitments.
A significant portion of our future contracted revenue is excluded from the amounts presented below in accordance with ASC 606. Variable consideration that is constrained or not required to be estimated as it reflects our efforts to perform is excluded from this disclosure. Additionally, we do not disclose information on the future performance obligations for any contract with an original expected duration of one year or less, or that are terminable by our customer with little or no termination penalties. Potential future performance obligations related to renewals that have not yet been exercised or are not certain of exercise are excluded from the amounts presented below. Revenues classified as Rental income and Sales-type lease revenue are also excluded from this table.
(In billions)
2024$0.6 
20252.1 
20261.9 
20271.8 
20280.6 
2029 and thereafter0.8 
Total estimated revenue on remaining performance obligations$7.8 
As of September 30, 2024, unsatisfied performance obligations included in the Consolidated Balance Sheets are $491 million and will be recognized as revenue as the obligations are satisfied, which is generally expected to occur over the next 20 years. A portion of this amount is not disclosed in the table above as it is deemed variable consideration due to volume variability.
v3.24.3
Supplemental Cash Flow Information (Tables)
 9 Months Ended
Sep. 30, 2024
Supplemental Cash Flow Elements [Abstract]  
Schedule of Cash Flow, Supplemental Disclosures
 Nine Months Ended 
September 30,
(In millions)20242023
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)$724 $724 
Income taxes paid2 4 
Cash paid for amounts included in the measurement of lease liabilities:
Payments on operating leases53 53 
Net cash provided by financing activities included:
Principal payments under finance lease obligations1 1 
Non-cash investing and financing activities:
Net transfers of property, plant and equipment (to)/from materials and supplies inventory— 8 
Net transfers of property, plant and equipment to lease receivable108 86 
ROU assets obtained in exchange for new operating lease obligations$34 $19 
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)20242023
Additions to property, plant and equipment$748 $662 
(Decrease)/Increase in capital accruals(28)6 
Total capital expenditures$720 $668 
v3.24.3
Description of Business and Basis of Presentation - Additional Information (Detail)
 9 Months Ended
Sep. 30, 2024
Accounting Policies [Abstract]  
Number of reportable segments 2
v3.24.3
Business Combinations and Asset Acquisitions (Details) - USD ($)
$ in Millions
 9 Months Ended
Jul. 31, 2024
May 29, 2024
Mar. 22, 2024
Sep. 30, 2024
Sep. 30, 2023
May 28, 2024
Business Acquisition [Line Items]            
Proceeds from Equity Method Investment, Distribution, Return of Capital       $ 138 $ 0  
Payments to Acquire Interest in Joint Venture       $ 414 $ 90  
Utica Midstream            
Business Acquisition [Line Items]            
Business Acquisition, Description of Acquired Entity     On March 22, 2024, MPLX used $625 million of cash on hand to purchase additional ownership interest in existing joint ventures and gathering assets (the “Utica Midstream Acquisition”), which will enhance our position in the Utica basin. Prior to the acquisition, we owned an indirect interest in Ohio Gathering Company L.L.C. (“OGC”) and a direct interest in Ohio Condensate Company L.L.C. (“OCC”) and now own a combined 73 percent interest in OGC, a 100 percent interest in OCC, and a 100 percent interest in a dry gas gathering system in the Utica basin, including 53 miles of gathering pipeline and three dehydration units with a combined capacity of approximately 620 MMcf/d.      
Payments to Acquire Businesses, Gross     $ 625      
Business Acquisition, Percentage of Voting Interests Acquired     100.00%      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net     $ 625      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets     $ 518      
Ohio Gathering Company L.L.C.            
Business Acquisition [Line Items]            
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage     73.00%      
Difference between carrying amount and underlying equity     $ 86      
Ohio Condensate Company, L.L.C.            
Business Acquisition [Line Items]            
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage     100.00%      
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage     62.00%      
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain     $ 20      
WPC Parent, LLC(3)            
Business Acquisition [Line Items]            
Gain (Loss) on Disposition of Stock in Subsidiary or Equity Method Investee   $ 151        
Proceeds from Equity Method Investment, Distribution, Return of Capital   $ 134        
WPC Parent, LLC(3) | Enbridge Inc.            
Business Acquisition [Line Items]            
Equity method investment, ownership percentage   19.00%        
WPC Parent, LLC(3) | MPLX LP [Member]            
Business Acquisition [Line Items]            
Equity method investment, ownership percentage   30.40%        
Whistler Pipeline LLC [Member] | MPLX LP [Member]            
Business Acquisition [Line Items]            
Equity method investment, ownership percentage           37.50%
BANGL, LLC            
Business Acquisition [Line Items]            
Equity method investment, ownership percentage 45.00%          
Difference between carrying amount and underlying equity $ 156          
Equity Method Investment, Addition Ownership Acquired 20.00%          
Payments to Acquire Interest in Joint Venture $ 210          
v3.24.3
Investments and Noncontrolling Interests (Schedule of Equity Method Investments) (Details) - USD ($)
$ in Millions
 9 Months Ended
Jul. 31, 2024
Sep. 30, 2024
Sep. 30, 2023
Mar. 22, 2024
Dec. 31, 2023
Schedule of Equity Method Investments          
Equity method investments   $ 4,558     $ 3,743
Payments to Acquire Interest in Joint Venture   414 $ 90    
BANGL, LLC          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage 45.00%        
Payments to Acquire Interest in Joint Venture $ 210        
Difference between carrying amount and underlying equity $ 156        
L&S          
Schedule of Equity Method Investments          
Equity method investments   $ 2,148     1,832
L&S | BANGL, LLC          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   45.00%      
Equity method investments [1]   $ 275     63
L&S | Illinois Extension Pipeline Company, L.L.C.          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   35.00%      
Equity method investments   $ 231     228
L&S | LOOP LLC          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   41.00%      
Equity method investments   $ 313     314
L&S | MarEn Bakken Company LLC(2)          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   25.00%      
Equity method investments [2]   $ 530     449
L&S | WPC Parent, LLC(3)          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   30.00%      
Equity method investments [3]   $ 206      
L&S | Whistler Pipeline LLC [Member]          
Schedule of Equity Method Investments          
Equity method investments [3]         214
L&S | Other VIEs and Non-VIEs          
Schedule of Equity Method Investments          
Equity method investments [4]   $ 593     564
L&S | Indirect Ownership Interest [Member] | Bakken Pipeline System [Member]          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   9.19%      
G&P          
Schedule of Equity Method Investments          
Equity method investments   $ 2,410     1,911
G&P | 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   $ 335     336
G&P | MarkWest Utica EMG, L.L.C.          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   59.00%      
Equity method investments   $ 717     676
G&P | Ohio Gathering Company L.L.C.          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   35.00%   36.00%  
Equity method investments [5]   $ 488     0
G&P | Sherwood Midstream LLC          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   50.00%      
Equity method investments   $ 492     500
G&P | Other VIEs and Non-VIEs          
Schedule of Equity Method Investments          
Equity method investments   $ 378     $ 399
G&P | Indirect Ownership Interest [Member] | Ohio Gathering Company L.L.C.          
Schedule of Equity Method Investments          
Equity method investment, ownership percentage   38.00%      
[1] In July 2024, we purchased an additional 20 percent ownership interest in BANGL, LLC, increasing our ownership interest to 45 percent, as discussed in Note 3.
[2] 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”).
[3] Reflects the dilution of MPLX’s ownership interest in Whistler Pipeline, LLC and the formation of a new entity, WPC Parent, LLC, as discussed in Note 3. The carrying value at September 30, 2024 represents our ownership in WPC Parent, LLC, and the carrying value at December 31, 2023 represents our ownership interest in Whistler Pipeline, LLC.
[4] Some investments included within Other have also been deemed to be VIEs.
[5] We acquired a 36 percent direct interest in OGC in the Utica Midstream Acquisition discussed in Note 3. We also hold a 38 percent indirect interest in OGC through our ownership interest in MarkWest Utica EMG, L.L.C.
v3.24.3
Related Party Loan (Details) - Revolving Credit Facility - Related Party [Member] - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2024
Dec. 31, 2023
Related Party Transaction [Line Items]    
Line of Credit Facility, Current Borrowing Capacity $ 1,500  
Debt Instrument, Description of Variable Rate Basis one-month term SOFR adjusted upward by 0.10 percent plus 1.25 percent  
Line of Credit, Current $ 0 $ 0
v3.24.3
Related Party Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Related Party [Member]        
Related Party Transaction [Line Items]        
Sales Revenue, Goods, Related Party, Net Zero $ 177 $ 192 $ 561 $ 540
v3.24.3
Related Party Expenses (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Related Party Transaction [Line Items]        
General and administrative expenses $ 107 $ 102 $ 323 $ 280
Related Party [Member]        
Related Party Transaction [Line Items]        
General and administrative expenses 73 72 217 197
Asset under Construction [Member] | Related Party [Member]        
Related Party Transaction [Line Items]        
Property, Plant and Equipment, Additions $ 44 $ 28 $ 124 $ 56
v3.24.3
Related Party Assest and Liabilities (Details) - USD ($)
$ in Millions
Sep. 30, 2024
Dec. 31, 2023
Related Party Transaction [Line Items]    
Receivables $ 742 $ 823
Other current assets 37 30
Right of use assets 271 264
Operating lease liabilities 49 45
Long-term deferred revenue 326 347
Related Party [Member]    
Related Party Transaction [Line Items]    
Receivables 625 587
Lease receivables 203 149
Prepaid 14 5
Other current assets 0 7
Current assets - related parties 842 748
Long-term lease receivables 711 789
Right of use assets 226 227
Unguaranteed residual asset 172 126
Long-term receivables 26 19
Noncurrent assets - related parties 1,135 1,161
Accounts payable [1] 264 278
Deferred revenue 89 81
Operating lease liabilities 1 1
Other current liabilities 354 360
Long-term operating lease liabilities 225 226
Long-term deferred revenue 95 99
Other Liabilities, Noncurrent 320 325
Revolving Credit Facility | Related Party [Member]    
Related Party Transaction [Line Items]    
Line of Credit, Current $ 0 $ 0
[1] There were no borrowings outstanding on the MPC Loan Agreement as of September 30, 2024 or December 31, 2023.
v3.24.3
Related Party Agreements and Transactions (Details) - Related Party [Member]
$ in Millions
Jun. 30, 2024
USD ($)
Related Party Transaction [Line Items]  
Lessor, Operating Lease Payments To Be Received, Increase Attributable To Terminalling Renewal $ 696
Sales-Type And Direct Financing Leases, Lease Receivable Payments To Be Received, Increase Attributable To Terminalling Renewal $ 90
v3.24.3
Equity - Changes in Partners Capital, Unit Rollforward (Details) - shares
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Stockholders Equity [Line Items]        
Balance at December 31, 2023     1,003,498,875  
Unit-based compensation awards     141,985  
Conversion of Series A preferred units     21,078,998  
Stock Repurchased and Retired During Period, Shares (1,800,000) 0 (5,473,621) 0
Balance at September 30, 2024 1,019,246,237   1,019,246,237  
v3.24.3
Equity (Unit Repurchase Program) (Details) - USD ($)
$ in Millions
Sep. 30, 2024
Aug. 02, 2022
Equity [Abstract]    
Stock Repurchase Program, Authorized Amount   $ 1,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount $ 620  
v3.24.3
Equity (Unit Repurchases) (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Equity [Abstract]        
Number of common units repurchased 1,800,000 0 5,473,621 0
Cash paid for common units repurchased(1) [1] $ 76 $ 0 $ 226 $ 0
Average cost per unit(1) [1] $ 42.89 $ 0 $ 41.32 $ 0
[1] Cash paid for common units repurchased and average cost per unit includes commissions paid to brokers during the period.
v3.24.3
Series A Preferred Units (Details)
 9 Months Ended
Sep. 30, 2024
shares
Preferred Units [Line Items]  
Partners' Capital Account, Units, Converted 21,078,998
Series A Preferred Stock [Member]  
Preferred Units [Line Items]  
Temporary Equity, Shares Outstanding 6,000,000
v3.24.3
Series B Redemption (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended
Feb. 15, 2023
Sep. 30, 2024
Jun. 30, 2024
Mar. 31, 2024
Sep. 30, 2023
Jun. 30, 2023
Mar. 31, 2023
Equity, Class of Treasury Stock [Line Items]              
Partners' Capital Account, Distributions   $ 879 $ 875 $ 864 $ 787 $ 785 $ 808
Series B Preferred Stock [Member]              
Equity, Class of Treasury Stock [Line Items]              
Preferred Stock, Redemption Terms MPLX exercised its right to redeem all 600,000 outstanding 6.875 percent Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the “Series B preferred units”). MPLX paid unitholders the Series B preferred unit redemption price of $1,000 per unit.            
Partners' Capital Account, Units, Redeemed 600,000            
Dividend rate, percentage 6.875%            
Preferred Stock, Redemption Price Per Share $ 1,000            
Partners' Capital Account, Distributions $ 21            
Distribution date Feb. 15, 2023            
v3.24.3
Equity - Cash Distributions (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 9 Months Ended
Nov. 15, 2024
Nov. 08, 2024
Oct. 29, 2024
Feb. 15, 2023
Sep. 30, 2024
Jun. 30, 2024
Mar. 31, 2024
Sep. 30, 2023
Jun. 30, 2023
Mar. 31, 2023
Sep. 30, 2024
Sep. 30, 2023
Distribution Made to Limited Partner [Line Items]                        
Distribution Made to Limited Partner, Cash Distributions Declared         $ 980     $ 876     $ 2,727 $ 2,479
Cash distributions declared per limited partner common unit         $ 0.9565 $ 0.8500 $ 0.8500 $ 0.8500 $ 0.7750 $ 0.7750    
Series A Preferred Stock [Member]                        
Distribution Made to Limited Partner [Line Items]                        
Distribution Made to Limited Partner, Cash Distributions Declared         $ 6     $ 25     21 71
Series B Preferred Stock [Member]                        
Distribution Made to Limited Partner [Line Items]                        
Distribution Made to Limited Partner, Cash Distributions Declared         0     0     0 5 [1]
Distribution date       Feb. 15, 2023                
Common Unit-holders Public                        
Distribution Made to Limited Partner [Line Items]                        
Distribution Made to Limited Partner, Cash Distributions Declared         $ 974     $ 851     $ 2,706 $ 2,403
Subsequent Event                        
Distribution Made to Limited Partner [Line Items]                        
Distribution Made to Limited Partner, Cash Distributions Declared     $ 974                  
Distribution Made to Limited Partner, Declaration Date     Oct. 29, 2024                  
Cash distributions declared per limited partner common unit     $ 0.9565                  
Subsequent Event | Common Unit-holders Public                        
Distribution Made to Limited Partner [Line Items]                        
Distribution date Nov. 15, 2024                      
Date of record   Nov. 08, 2024                    
[1] The nine months ended September 30, 2023 includes the portion of the $21 million distribution paid to the Series B preferred unitholders on February 15, 2023 that was earned during the period prior to redemption.
v3.24.3
Net Income Per Limited Partner Unit - Basic and Diluted Earnings Per Unit (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Schedule Of Earnings Per Share Basic And Diluted [Line Items]        
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent [1] $ 1,037 $ 918 $ 3,218 $ 2,794
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic 0 1 7 9
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted 0 1 7 9
Impact of redemption of Series B preferred units 0 0 0 5
Net Income (Loss) Available to Common Stockholders, Basic 1,031 892 3,190 2,704
Net Income (Loss) Available to Common Stockholders, Diluted $ 1,031 $ 892 $ 3,190 $ 2,704
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 1 1 1 1
Weighted average units outstanding:        
Common - basic 1,020 1,001 1,016 1,001
Common - diluted 1,020 1,001 1,016 1,001
Net income attributable to MPLX LP per limited partner unit:        
Common - basic $ 1.01 $ 0.89 $ 3.14 $ 2.70
Common - diluted $ 1.01 $ 0.89 $ 3.14 $ 2.70
Series A Preferred Stock [Member]        
Schedule Of Earnings Per Share Basic And Diluted [Line Items]        
Distributed Earnings $ 6 $ 25 $ 21 $ 71
Series B Preferred Stock [Member]        
Schedule Of Earnings Per Share Basic And Diluted [Line Items]        
Distributed Earnings $ 0 $ 0 $ 0 $ 5
[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.
v3.24.3
Segment Information (Details)
 9 Months Ended
Sep. 30, 2024
Segment Reporting [Abstract]  
Number of reportable segments 2
v3.24.3
Segment Information - Segment Adjusted EBITDA (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Mar. 29, 2024
Segment Reporting Information [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax $ 2,345 $ 2,283 $ 6,772 $ 6,486  
Sales-type lease revenue 34 34 102 101  
Income from equity method investments 149 159 631 438  
Revenues 2,972 2,912 8,870 8,315  
Capital Expenditure     720 668  
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures         $ 92
Nonrelated Party [Member]          
Segment Reporting Information [Line Items]          
Rental income 63 61 187 181  
Other Income 7 7 58 28  
L&S          
Segment Reporting Information [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax 1,163 1,136 3,381 3,237  
L&S | Nonrelated Party [Member]          
Segment Reporting Information [Line Items]          
Revenues 196 207 779 564  
G&P          
Segment Reporting Information [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax 1,182 1,147 3,391 3,249  
G&P | Nonrelated Party [Member]          
Segment Reporting Information [Line Items]          
Revenues 1,285 1,248 3,705 3,553  
Operating Segments          
Segment Reporting Information [Line Items]          
Adjusted EBITDA 1,714 1,596 5,002 4,646  
Operating Segments | L&S          
Segment Reporting Information [Line Items]          
Rental income 223 216 666 638  
Sales-type lease revenue 118 129 359 379  
Income from equity method investments 80 95 429 248  
Other Income 33 15 113 47  
Revenues [1] 1,617 1,591 4,948 4,549  
Adjusted EBITDA [2] 1,157 1,091 3,384 3,139  
Capital Expenditure 112 73 299 251  
Investments in unconsolidated affiliates(3) 10 7 103 [3] 23  
Operating Segments | G&P          
Segment Reporting Information [Line Items]          
Rental income 56 52 165 155  
Sales-type lease revenue 34 34 102 101  
Income from equity method investments 69 64 202 190  
Other Income 14 24 62 71  
Revenues [1] 1,355 1,321 3,922 3,766  
Adjusted EBITDA [2] 557 505 1,618 1,507  
Capital Expenditure 189 151 421 417  
Investments in unconsolidated affiliates(3) 22 6 83 67  
Service [Member] | Operating Segments | L&S          
Segment Reporting Information [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax 1,158 1,130 3,367 3,223  
Service [Member] | Operating Segments | G&P          
Segment Reporting Information [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax 617 549 1,785 1,620  
Product [Member] | Operating Segments | L&S          
Segment Reporting Information [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax 5 6 14 14  
Product [Member] | Operating Segments | G&P          
Segment Reporting Information [Line Items]          
Revenue from Contract with Customer, Excluding Assessed Tax $ 565 $ 598 $ 1,606 $ 1,629  
[1] Within the total segment revenues and other income amounts presented above, third party revenues for the L&S segment were $196 million and $779 million for the three and nine months ended September 30, 2024, respectively, and $207 million and $564 million for the three and nine months ended September 30, 2023, respectively. Third party revenues for the G&P segment were $1,285 million and $3,705 million for the three and nine months ended September 30, 2024, respectively, and $1,248 million and $3,553 million for the three and nine months ended September 30, 2023, respectively.
[2] See below for the reconciliation from Segment Adjusted EBITDA to Net income.
[3] The nine months ended September 30, 2024 includes a contribution of $92 million to Dakota Access to fund our share of a debt repayment by the joint venture.
v3.24.3
Segment Information - Reconciliation to Net Income (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Segment Reporting, Revenue Reconciling Item [Line Items]        
Depreciation and Amortization [1] $ 322 $ 301 $ 959 $ 907
Net interest and other financial costs 226 225 692 701
Income from equity method investments 149 159 631 438
Net income 1,047 928 3,248 2,822
Operating Segments        
Segment Reporting, Revenue Reconciling Item [Line Items]        
Adjusted EBITDA 1,714 1,596 5,002 4,646
Segment Reconciling Items [Member]        
Segment Reporting, Revenue Reconciling Item [Line Items]        
Distributions/adjustments related to equity method investments 253 208 671 551
Adjusted EBITDA attributable to noncontrolling interests 11 11 33 31
Garyville incident response costs 0 (63) [2] 0 (63) [2]
Other Noncash Income (Expense) [3] 26 41 96 71
L&S        
Segment Reporting, Revenue Reconciling Item [Line Items]        
Depreciation and Amortization 132 130 393 399
L&S | Operating Segments        
Segment Reporting, Revenue Reconciling Item [Line Items]        
Adjusted EBITDA [4] 1,157 1,091 3,384 3,139
Income from equity method investments 80 95 429 248
G&P        
Segment Reporting, Revenue Reconciling Item [Line Items]        
Depreciation and Amortization 190 171 566 508
G&P | Operating Segments        
Segment Reporting, Revenue Reconciling Item [Line Items]        
Adjusted EBITDA [4] 557 505 1,618 1,507
Income from equity method investments $ 69 $ 64 $ 202 $ 190
[1] Depreciation and amortization attributable to L&S was $132 million and $393 million for the three and nine months ended September 30, 2024, respectively, and $130 million and $399 million for the three and nine months ended September 30, 2023, respectively. Depreciation and amortization attributable to G&P was $190 million and $566 million for the three and nine months ended September 30, 2024, respectively, and $171 million and $508 million for the three and nine months ended September 30, 2023, respectively.
[2] In August 2023, a naphtha release and resulting fire occurred at our Garyville Tank Farm resulting in the loss of four storage tanks with a combined shell capacity of 894 thousand barrels. We incurred $63 million of incident response costs during the three and nine months ended September 30, 2023.
[3] Includes unrealized derivative gain/(loss), equity-based compensation, provision for income taxes, and other miscellaneous items.
[4] See below for the reconciliation from Segment Adjusted EBITDA to Net income.
v3.24.3
Property, Plant and Equipment (Summary of Property, Plant and Equipment) (Details) - USD ($)
$ in Millions
Sep. 30, 2024
Dec. 31, 2023
Property, Plant and Equipment [Line Items]    
Gross PP&E $ 28,124 $ 27,385
Accumulated Depreciation 8,971 8,121
Net PP&E 19,153 19,264
L&S    
Property, Plant and Equipment [Line Items]    
Gross PP&E 13,037 12,779
Accumulated Depreciation 4,421 4,037
Net PP&E 8,616 8,742
G&P    
Property, Plant and Equipment [Line Items]    
Gross PP&E 15,087 14,606
Accumulated Depreciation 4,550 4,084
Net PP&E $ 10,537 $ 10,522
v3.24.3
Fair Values - Recurring - Balance Sheet Location Table (Details) - USD ($)
$ in Millions
Sep. 30, 2024
Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset, Subject to Master Netting Arrangement, before Offset $ 1 $ 0
Derivative Liability, Subject to Master Netting Arrangement, before Offset 69 61
Fair Value, Inputs, Level 2 [Member] | Commodity Contract [Member] | Other current assets [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset, Subject to Master Netting Arrangement, before Offset 1 0
Fair Value, Inputs, Level 2 [Member] | Commodity Contract [Member] | Other Current Liabilities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liability, Subject to Master Netting Arrangement, before Offset 0 0
Fair Value, Inputs, Level 3 [Member] | Embedded Derivative Financial Instruments [Member] | Other current assets [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset, Subject to Master Netting Arrangement, before Offset 0 0
Fair Value, Inputs, Level 3 [Member] | Embedded Derivative Financial Instruments [Member] | Other Noncurrent Assets [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Asset, Subject to Master Netting Arrangement, before Offset 0 0
Fair Value, Inputs, Level 3 [Member] | Embedded Derivative Financial Instruments [Member] | Other Current Liabilities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liability, Subject to Master Netting Arrangement, before Offset 10 11
Fair Value, Inputs, Level 3 [Member] | Embedded Derivative Financial Instruments [Member] | Other Noncurrent Liabilities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative Liability, Subject to Master Netting Arrangement, before Offset $ 59 $ 50
v3.24.3
Fair Values - Recurring - Significant Unobservable Inputs in Level 3 Valuation (Details) - Embedded Derivative Financial Instruments [Member]
 9 Months Ended
Sep. 30, 2024
$ / gal
Natural Gas [Member]  
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]  
Embedded Derivative Renewal Term 5 years
Fair Value, Inputs, Level 3 [Member]  
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]  
Derivative, Average Forward Price 0.85
Fair Value Inputs Probability of Renewal 100.00%
Minimum [Member] | Fair Value, Inputs, Level 3 [Member]  
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]  
Derivative, Forward Price 0.67
Maximum [Member] | Fair Value, Inputs, Level 3 [Member]  
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]  
Derivative, Forward Price 1.45
v3.24.3
Changes in Level 3 Fair Value Measurements (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Beginning balance $ (69) $ (53) $ (61) $ (61)
Unrealized and realized (loss)/gain included in Net Income(1) [1] (3) (10) (18) (7)
Settlements 3 3 10 8
Ending balance $ (69) $ (60) $ (69) $ (60)
[1] (Loss)/gain on derivatives embedded in commodity contracts are recorded in Purchased product costs in the Consolidated Statements of Income.
v3.24.3
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, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Fair Value Disclosures [Abstract]        
The amount of total loss for the period included in earnings attributable to the change in unrealized (loss)/gain relating to liabilities still held at end of period $ (3) $ (9) $ (15) $ (6)
v3.24.3
Fair Values - Reported (Details) - USD ($)
$ in Millions
Sep. 30, 2024
Dec. 31, 2023
Estimate of Fair Value Measurement [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-Term Debt, Fair Value [1] $ 21,494 $ 19,377
Reported Value Measurement [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Long-Term Debt, Fair Value [1] $ 22,209 $ 20,547
[1] Any amounts outstanding under the MPC Loan Agreement are not included in the table above, as the carrying value approximates fair value. This balance is reflected in Current liabilities - related parties in the Consolidated Balance Sheets.
v3.24.3
Schedule of Outstanding Derivative Positions (Details)
Sep. 30, 2024
gal
Propane | Short | Over-the-Counter  
Derivative [Line Items]  
Derivative, Nonmonetary Notional Amount, Volume 14,427,000
v3.24.3
Derivative Financial Instruments - Embedded Derivatives in Commodity Contracts (Details) - Embedded Derivative Financial Instruments [Member]
$ in Millions
 9 Months Ended
Sep. 30, 2024
USD ($)
Dec. 31, 2023
USD ($)
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]    
Derivative [Line Items]    
Derivative Liability $ (69) $ (61)
Natural Gas [Member]    
Derivative [Line Items]    
Number of Renewals 1  
Embedded Derivative Renewal Term 5 years  
v3.24.3
Derivatives Financial Instruments - Derivative Income Statement Location (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Derivative [Line Items]        
Derivative, Gain (Loss) on Derivative, Net $ 1 $ (15) $ (16) $ (2)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Net income Net income Net income Net income
Purchased product costs        
Derivative [Line Items]        
Realized gain (loss) $ (3) $ (3) $ (10) $ (8)
Unrealized Gain (Loss) on Derivatives and Commodity Contracts 0 (7) (8) 1
Derivative, Gain (Loss) on Derivative, Net (3) (10) (18) (7)
Product Sales        
Derivative [Line Items]        
Realized gain (loss) 1 3 1 3
Unrealized Gain (Loss) on Derivatives and Commodity Contracts 3 (8) 1 2
Derivative, Gain (Loss) on Derivative, Net $ 4 $ (5) $ 2 $ 5
v3.24.3
Debt - Summary of Outstanding Borrowings (Detail) - USD ($)
$ in Millions
May 20, 2024
Sep. 30, 2024
Dec. 31, 2023
Debt Instrument [Line Items]      
MPLX Credit Agreement   $ 0 $ 0
Finance lease obligations   6 6
Debt and Lease Obligation   22,356 20,706
Unamortized debt issuance costs   (129) (122)
Unamortized discount   (141) (153)
Amounts due within one year   2,836 1,135
Total long-term debt due after one year   19,250 19,296
Senior Note Due June 2034 [Domain] | Senior Notes [Member]      
Debt Instrument [Line Items]      
Debt Instrument, Face Amount $ 1,650    
Debt Instrument, Interest Rate, Stated Percentage 5.50%    
Percent of Par 98.778%    
Debt Instrument, Issuance Date May 20, 2024    
MPLX LP [Member]      
Debt Instrument [Line Items]      
Senior Notes   22,307 20,657
MPLX LP [Member] | Senior Notes Due December 2024 | Senior Notes [Member]      
Debt Instrument [Line Items]      
Debt Instrument, Face Amount   $ 1,149  
Debt Instrument, Interest Rate, Stated Percentage   4.875%  
MPLX LP [Member] | Senior Notes Due February 2025 | Senior Notes [Member]      
Debt Instrument [Line Items]      
Debt Instrument, Face Amount   $ 500  
Debt Instrument, Interest Rate, Stated Percentage   4.00%  
MarkWest [Member]      
Debt Instrument [Line Items]      
Senior Notes   $ 12 12
MarkWest [Member] | Senior Notes Due December 2024 | Senior Notes [Member]      
Debt Instrument [Line Items]      
Debt Instrument, Face Amount   $ 1  
Debt Instrument, Interest Rate, Stated Percentage   4.875%  
ANDX LP [Member]      
Debt Instrument [Line Items]      
Senior Notes   $ 31 $ 31
v3.24.3
Credit Agreement (Detail) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2024
Dec. 31, 2023
Debt Instrument [Line Items]    
Long-term Line of Credit $ 0 $ 0
MPLX Revolving Credit Facility due June 2027    
Debt Instrument [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity 2,000  
Letter of Credit, Issuing Capacity $ 150  
Debt Instrument, Description of Variable Rate Basis Adjusted Term SOFR or the Alternate Base Rate, both as defined in the MPLX Credit Agreement, plus an applicable margin.  
v3.24.3
Senior Notes (Details) - Senior Notes [Member] - USD ($)
$ in Millions
Sep. 30, 2024
May 20, 2024
Senior Note Due June 2034 [Domain]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage   5.50%
Percent of Par   98.778%
Debt Instrument, Face Amount   $ 1,650
Senior Notes Due December 2024 | MPLX LP [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.875%  
Debt Instrument, Face Amount $ 1,149  
Senior Notes Due December 2024 | MarkWest [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.875%  
Debt Instrument, Face Amount $ 1  
Senior Notes Due February 2025 | MPLX LP [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.00%  
Debt Instrument, Face Amount $ 500  
Minimum [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 1.75%  
Maximum [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.65%  
v3.24.3
Interest and Other Financial Costs (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Other Income and Expenses [Abstract]        
Interest expense $ 251 $ 227 $ 717 $ 684
Other financial costs 15 14 57 55
Interest income (35) (12) (68) (27)
Capitalized interest (5) (4) (14) (11)
Interest and Debt Expense, Total $ 226 $ 225 $ 692 $ 701
v3.24.3
Revenue Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax $ 2,345 $ 2,283 $ 6,772 $ 6,486
Revenue Not from Contract with Customer, Other [1] 627 629 2,098 1,829
Revenues 2,972 2,912 8,870 8,315
L&S        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,163 1,136 3,381 3,237
L&S | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues [2] 1,617 1,591 4,948 4,549
G&P        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,182 1,147 3,391 3,249
G&P | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues [2] 1,355 1,321 3,922 3,766
Service [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 709 641 2,050 1,881
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 1,066 1,038 3,102 2,962
Service [Member] | L&S        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 101 97 286 272
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 1,057 1,033 3,081 2,951
Service [Member] | L&S | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,158 1,130 3,367 3,223
Service [Member] | G&P        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 608 544 1,764 1,609
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 9 5 21 11
Service [Member] | G&P | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 617 549 1,785 1,620
Service, Other [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 86 75 265 214
Service, Other [Member] | L&S        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 0 0 0 0
Service, Other [Member] | G&P        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 86 75 265 214
Product [Member]        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 433 478 1,191 1,274
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 51 51 164 155
Product [Member] | L&S        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 1 2 4 4
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 4 4 10 10
Product [Member] | L&S | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 5 6 14 14
Product [Member] | G&P        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax, Third parties 432 476 1,187 1,270
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties 47 47 154 145
Product [Member] | G&P | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax $ 565 $ 598 $ 1,606 $ 1,629
[1] Non-ASC 606 Revenue includes rental income, sales-type lease revenue, income from equity method investments, and other income.
[2] Within the total segment revenues and other income amounts presented above, third party revenues for the L&S segment were $196 million and $779 million for the three and nine months ended September 30, 2024, respectively, and $207 million and $564 million for the three and nine months ended September 30, 2023, respectively. Third party revenues for the G&P segment were $1,285 million and $3,705 million for the three and nine months ended September 30, 2024, respectively, and $1,248 million and $3,553 million for the three and nine months ended September 30, 2023, respectively.
v3.24.3
Revenue Contract Balances (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Dec. 31, 2023
Dec. 31, 2022
Contract assets $ 2 $ 2 $ 3 $ 21
Contract assets, additions/(deletions) 0 (19)    
Contract with Customer, Asset, Reclassified to Receivable [1] (1) 0    
Long-term contract assets 0 1 1 1
Contract with Customer, Asset Increase (Decrease), Noncurrent (1) 0    
Contract With Customer Non Current Asset Reclassified To Receivable [Line Items] [1] 0 0    
Long-term deferred revenue 326   347  
Long-term contract liabilities   0   2
Contract Liability, Noncurrent, Period Increase (Decrease)   (2)    
Contract Liability, Noncurrent, Revenue Recognized [1]   0    
Liability, change in timeframe, performance obligation satisfied, revenue recognized 0 0    
Nonrelated Party [Member]        
Deferred revenue 82 50 59 57
Deferred revenue, revenue recognized [1] (42) (31)    
Deferred Revenue, Additions 65 24    
Long-term deferred revenue 322 292 344 216
Long-term deferred revenue, additions/(deletions) (22) 76    
Long-term deferred revenue, revenue recognized [1] 0 0    
Related Party [Member]        
Deferred revenue 89   81  
Deferred revenue, revenue recognized [1] (50) (72)    
Deferred Revenue, Additions 56 63    
Deferred Revenue from Contracts with Customers, Current 53 54 47 63
Long-term deferred revenue 95   99  
Long-term deferred revenue, additions/(deletions) 5 5    
Long-term deferred revenue, revenue recognized [1] 0 0    
Deferred Revenue from Contracts with Customers, Noncurrent $ 34 $ 30 $ 29 $ 25
[1] No significant revenue was recognized related to past performance obligations in the current periods.
v3.24.3
Revenue Remaining Performance Obligations (Details)
$ in Millions
Sep. 30, 2024
USD ($)
Revenue from Contract with Customer [Abstract]  
Contract with customer, liability $ 491
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, Remaining Performance Obligation, Amount $ 7,800
Maximum [Member]  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 20 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, years 3 months
Revenue, Remaining Performance Obligation, Amount $ 600
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
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 $ 2,100
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
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 $ 1,900
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 $ 1,800
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 $ 600
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 15 years
Revenue, Remaining Performance Obligation, Amount $ 800
v3.24.3
Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Details) - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Supplemental Cash Flow Elements [Abstract]    
Interest paid (net of amounts capitalized) $ 724 $ 724
Income taxes paid 2 4
Operating Lease, Payments 53 53
Finance Lease, Principal Payments 1 1
Net transfers of property, plant and equipment (to)/from materials and supplies inventory 0 8
Property, Plant and Equipment, Transfers and Changes 108 86
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability $ 34 $ 19
v3.24.3
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, 2024
Sep. 30, 2023
Supplemental Cash Flow Elements [Abstract]    
Additions to property, plant and equipment $ 748 $ 662
(Decrease)/Increase in capital accruals (28) 6
Total capital expenditures $ 720 $ 668
v3.24.3
Commitments and Contingencies - Additional Information (Detail) - USD ($)
$ in Millions
 1 Months Ended 9 Months Ended
Dec. 15, 2020
Jul. 31, 2020
Sep. 30, 2024
Dec. 31, 2023
Commitments And Contingencies [Line Items]        
Accrued liabilities for environmental remediation     $ 15 $ 19
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]     Other current liabilities, Long-term liabilities - related parties Other current liabilities, Long-term liabilities - related parties
Loss Contingency, Damages Sought, Value   $ 187    
Loss Contingency, Damages Paid, Value $ 4      
Guarantor Obligations, Origin and Purpose     Guarantees related to indebtedness of equity method investeesWe hold a 9.19 percent indirect interest in Dakota Access, which owns and operates the Bakken Pipeline system. In 2020, the U.S. District Court for the District of Columbia (the “D.D.C.”) ordered the United States Army Corps of Engineers (“Army Corps”), which granted permits and an easement for the Bakken Pipeline system, to prepare an environmental impact statement (“EIS”) relating to an easement under Lake Oahe in North Dakota. The D.D.C. later vacated the easement. The Army Corps issued a draft EIS in September 2023 detailing various options for the easement going forward, including denying the easement, approving the easement with additional measures, rerouting the easement, or approving the easement with no changes. The Army Corps has not selected a preferred alternative, but will make a decision in its final review, after considering input from the public and other agencies. The pipeline remains operational while the Army Corps finalizes its decision which will follow the issuance of the final EIS. According to public statements from Army Corps officials, the EIS is now expected to be issued in 2025.We have entered into a Contingent Equity Contribution Agreement whereby MPLX LP, along with the other joint venture owners in the Bakken Pipeline system, has agreed to make equity contributions to the joint venture upon certain events occurring to allow the entities that own and operate the Bakken Pipeline system to satisfy their senior note payment obligations. The senior notes were issued to repay amounts owed by the pipeline companies to fund the cost of construction of the Bakken Pipeline system. If the vacatur of the easement results in a temporary shutdown of the pipeline, MPLX would have to contribute its 9.19 percent pro rata share of funds required to pay interest accruing on the notes and any portion of the principal that matures while the pipeline is shut down. MPLX also expects to contribute its 9.19 percent pro rata share of any costs to remediate any deficiencies to reinstate the easement and/or return the pipeline into operation. If the vacatur of the easement results in a permanent shutdown of the pipeline, MPLX would have to contribute its 9.19 percent pro rata share of the cost to redeem the bonds (including the one percent redemption premium required pursuant to the indenture governing the notes) and any accrued and unpaid interest. As of September 30, 2024, our maximum potential undiscounted payments under the Contingent Equity Contribution Agreement were approximately $78 million.  
Financial Guarantee [Member] | Bakken Pipeline System [Member] | Guarantee of Indebtedness of Others [Member]        
Commitments And Contingencies [Line Items]        
Guarantor Obligations, Maximum Exposure, Undiscounted     $ 78  
Performance Guarantee | WPC Parent, LLC(3)        
Commitments And Contingencies [Line Items]        
Guarantor Obligations, Maximum Exposure, Undiscounted     $ 82