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v3.26.1

Debt - Summary of Outstanding Borrowings (Detail) - USD ($) $ in Millions | Mar. 31, 2026 | Dec. 31, 2025 | Aug. 11, 2025
--- | --- | --- | ---
Debt Instrument [Line Items] |  |  |
Finance lease obligations | $ 6 | $ 6 |
Debt and Lease Obligation | 26,006 | 26,006 |
Unamortized debt issuance costs | (185) | (174) |
Unamortized discount | (187) | (179) |
Amounts due within one year | 1,251 | 1,502 |
Total long-term debt due after one year | 24,383 | 24,151 |
Senior Notes [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Debt Instrument, Face Amount |  |  | $ 4,500
MPLX LP [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Senior Notes | 25,969 | 25,969 |
ANDX LP [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Senior Notes | $ 31 | $ 31 |

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