Business Combinations and Asset Acquisitions	3 Months Ended
Mar. 31, 2024
Business Combination and Asset Acquisition [Abstract]
Business Combination Disclosure [Text Block]	Acquisition 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 (“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. 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 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 preliminary determination of 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.

On March 22, 2024, MPLX used $625 million of cash on hand to purchase additional ownership interest in existing joint ventures and gathering assets (“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. 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 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 preliminary determination of 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.