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Investments and Noncontrolling Interests (Schedule of Equity Method Investments) (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024
Schedule of Equity Method Investments |  |  |  |  |
Equity method investments |  | $ 4,751 |  |  | $ 4,531
Investments - redemptions, repayments, return of capital and sales proceeds |  | 21 |  | $ 0 |
Contribution of Net Assets |  | 115 | [1] | $ 0 |
MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C(3) |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Investments - redemptions, repayments, return of capital and sales proceeds |  | 21 |  |  |
Contribution of Property |  | 125 |  |  |
Crude Oil and Products Logistics |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investments |  | $ 1,606 |  |  | 1,595
Crude Oil and Products Logistics | Illinois Extension Pipeline Company, L.L.C. |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 35.00% |  |  |
Equity method investments |  | $ 225 |  |  | 218
Crude Oil and Products Logistics | LOOP LLC |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 41.00% |  |  |
Equity method investments |  | $ 314 |  |  | 310
Crude Oil and Products Logistics | MarEn Bakken Company LLC(1) |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 25.00% |  |  |
Equity method investments | [2] | $ 521 |  |  | 526
Crude Oil and Products Logistics | Other VIEs and Non-VIEs |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investments | [3] | $ 546 |  |  | 541
Crude Oil and Products Logistics | Indirect Ownership Interest [Member] | Bakken Pipeline System [Member] |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 9.19% |  |  |
Natural Gas and NGL Services |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investments |  | $ 3,145 |  |  | 2,936
Natural Gas and NGL Services | BANGL, LLC |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 45.00% |  |  |
Equity method investments |  | $ 279 |  |  | 281
Natural Gas and NGL Services | MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C(3) |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 67.00% |  |  |
Equity method investments |  | $ 428 | [4] |  | 329
Natural Gas and NGL Services | MarkWest Utica EMG, L.L.C. |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 60.00% |  |  |
Equity method investments |  | $ 782 |  |  | 742
Natural Gas and NGL Services | Ohio Gathering Company L.L.C. |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 34.00% |  |  |
Equity method investments | [5] | $ 464 |  |  | 470
Natural Gas and NGL Services | Sherwood Midstream LLC |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 50.00% |  |  |
Equity method investments |  | $ 485 |  |  | 488
Natural Gas and NGL Services | WPC Parent, LLC |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 30.00% |  |  |
Equity method investments |  | $ 243 |  |  | 208
Natural Gas and NGL Services | Other VIEs and Non-VIEs |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investments | [3] | $ 464 |  |  | $ 418
Natural Gas and NGL Services | Indirect Ownership Interest [Member] | Ohio Gathering Company L.L.C. |  |  |  |  |
Schedule of Equity Method Investments |  |  |  |  |
Equity method investment, ownership percentage |  | 39.00% |  |  |
[1] | (1) Represents the book value of assets contributed by MPLX to a joint venture.
[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] | Some investments included within Other have also been deemed to be VIEs.
[4] | On March 31, 2025, MPLX contributed a 100 percent owned subsidiary with a fair value of $125 million to MarkWest EMG Jefferson Dry Gas Gathering Company, L.L.C. MPLX received a special distribution of $21 million as a result of the transaction, which is reflected as a return of capital on the consolidated statement of cash flows.
[5] | MPLX also holds a 39 percent indirect interest in OGC through our ownership interest in MarkWest Utica EMG, L.L.C.

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