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Debt (Summary of Outstanding Borrowings) (Details) - USD ($) $ in Millions |  |  | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Aug. 11, 2025 | Mar. 10, 2025 | Dec. 31, 2025 | Apr. 09, 2025 | Feb. 18, 2025 | Dec. 31, 2024 | Dec. 01, 2024 | May 20, 2024
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Finance Lease, Liability | [1] |  |  | $ 6 |  |  | $ 6 |  |
Debt and capital lease obligations |  |  |  | 26,006 |  |  | 21,206 |  |
Unamortized debt issuance costs |  |  |  | 174 |  |  | 126 |  |
Unamortized discount |  |  |  | 179 |  |  | 132 |  |
Debt, Current |  |  |  | 1,502 |  |  | 1,693 |  |
Total long-term debt due after one year |  |  |  | 24,151 |  |  | 19,255 |  |
MPLX Revolving Credit Facility due July 2027 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Outstanding balance |  |  |  | 0 |  |  |  |  |
MPLX Revolving Credit Facility due July 2024 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Outstanding balance |  |  |  |  |  |  | 0 |  |
Senior Notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount |  | $ 4,500 |  |  |  |  |  |  |
Senior Notes | Senior Note Due June 2034 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  |  |  |  |  |  |  |  | 5.50%
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  | $ 1,650
Senior Notes | Senior Notes Due February 2031 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  | 4.80% |  |  |  |  |  |  |
Maturity Date |  | Feb. 15, 2031 |  |  |  |  |  |  |
Debt Instrument, Face Amount | [2] | $ 1,250 |  |  |  |  |  |  |
Senior Notes | Senior Notes Due January 2033 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  | 5.00% |  |  |  |  |  |  |
Maturity Date |  | Jan. 15, 2033 |  |  |  |  |  |  |
Debt Instrument, Face Amount | [2] | $ 750 |  |  |  |  |  |  |
Senior Notes | Senior Notes Due April 2035 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  |  | 5.40% |  |  |  |  |  |
Maturity Date |  |  | Apr. 01, 2035 |  |  |  |  |  |
Debt Instrument, Face Amount | [3] |  | $ 1,000 |  |  |  |  |  |
Senior Notes | Senior Notes Due September 2035 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  | 5.40% |  |  |  |  |  |  |
Maturity Date |  | Sep. 15, 2035 |  |  |  |  |  |  |
Debt Instrument, Face Amount | [2] | $ 1,500 |  |  |  |  |  |  |
Senior Notes | Senior Notes Due April 2055 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  |  | 5.95% |  |  |  |  |  |
Maturity Date |  |  | Apr. 01, 2055 |  |  |  |  |  |
Debt Instrument, Face Amount | [3] |  | $ 1,000 |  |  |  |  |  |
Senior Notes | Senior Notes Due September 2055 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  | 6.20% |  |  |  |  |  |  |
Maturity Date |  | Sep. 15, 2055 |  |  |  |  |  |  |
Debt Instrument, Face Amount | [2] | $ 1,000 |  |  |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due December 2024 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  |  |  |  |  |  |  | 4.875% |
MPLX LP | Senior Notes | Senior Notes Due February 2025 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 0 |  |  | 500 |  |
Interest Rate |  |  |  | 4.00% |  | 4.00% |  |  |
Maturity Date |  |  |  | Feb. 15, 2025 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due June 2025 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 0 |  |  | 1,189 |  |
Interest Rate |  |  |  | 4.875% | 4.875% |  |  |  |
Maturity Date |  |  |  | Jun. 01, 2025 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due March 2026 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,500 |  |  | 1,500 |  |
Interest Rate |  |  |  | 1.75% |  |  |  |  |
Maturity Date |  |  |  | Mar. 01, 2026 |  |  |  |  |
MPLX LP | Senior Notes | 4.125% senior notes due March 2027 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,250 |  |  | 1,250 |  |
Interest Rate |  |  |  | 4.125% |  |  |  |  |
Maturity Date |  |  |  | Mar. 01, 2027 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due December 2027 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 732 |  |  | 732 |  |
Interest Rate |  |  |  | 4.25% |  |  |  |  |
Maturity Date |  |  |  | Dec. 01, 2027 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due March 2028 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,250 |  |  | 1,250 |  |
Interest Rate |  |  |  | 4.00% |  |  |  |  |
Maturity Date |  |  |  | Mar. 15, 2028 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due February 2029 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 750 |  |  | 750 |  |
Interest Rate |  |  |  | 4.80% |  |  |  |  |
Maturity Date |  |  |  | Feb. 15, 2029 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due August 2030 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,500 |  |  | 1,500 |  |
Interest Rate |  |  |  | 2.65% |  |  |  |  |
Maturity Date |  |  |  | Aug. 15, 2030 |  |  |  |  |
MPLX LP | Senior Notes | Senior Note Due September 2032 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,000 |  |  | 1,000 |  |
Interest Rate |  |  |  | 4.95% |  |  |  |  |
Maturity Date |  |  |  | Sep. 01, 2032 |  |  |  |  |
MPLX LP | Senior Notes | Senior Note Due March 2033 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,100 |  |  | 1,100 |  |
Interest Rate |  |  |  | 5.00% |  |  |  |  |
Maturity Date |  |  |  | Mar. 01, 2033 |  |  |  |  |
MPLX LP | Senior Notes | Senior Note Due June 2034 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,650 |  |  | 1,650 |  |
Interest Rate |  |  |  | 5.50% |  |  |  |  |
Maturity Date |  |  |  | Jun. 01, 2034 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due April 2038 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,750 |  |  | 1,750 |  |
Interest Rate |  |  |  | 4.50% |  |  |  |  |
Maturity Date |  |  |  | Apr. 15, 2038 |  |  |  |  |
MPLX LP | Senior Notes | 5.200% senior notes due March 2047 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,000 |  |  | 1,000 |  |
Interest Rate |  |  |  | 5.20% |  |  |  |  |
Maturity Date |  |  |  | Mar. 01, 2047 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due December 2047 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 487 |  |  | 487 |  |
Interest Rate |  |  |  | 5.20% |  |  |  |  |
Maturity Date |  |  |  | Dec. 01, 2047 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due April 2048 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,500 |  |  | 1,500 |  |
Interest Rate |  |  |  | 4.70% |  |  |  |  |
Maturity Date |  |  |  | Apr. 15, 2048 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due February 2049 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,500 |  |  | 1,500 |  |
Interest Rate |  |  |  | 5.50% |  |  |  |  |
Maturity Date |  |  |  | Feb. 15, 2049 |  |  |  |  |
MPLX LP | Senior Notes | Senior Note Due March 2052 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,500 |  |  | 1,500 |  |
Interest Rate |  |  |  | 4.95% |  |  |  |  |
Maturity Date |  |  |  | Mar. 14, 2052 |  |  |  |  |
MPLX LP | Senior Notes | Senior Note Due March 2053 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 500 |  |  | 500 |  |
Interest Rate |  |  |  | 5.65% |  |  |  |  |
Maturity Date |  |  |  | Mar. 01, 2053 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due April 2058 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 500 |  |  | 500 |  |
Interest Rate |  |  |  | 4.90% |  |  |  |  |
Maturity Date |  |  |  | Apr. 15, 2058 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due February 2031 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,250 |  |  | 0 |  |
Interest Rate |  |  |  | 4.80% |  |  |  |  |
Maturity Date |  |  |  | Feb. 15, 2031 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due January 2033 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 750 |  |  | 0 |  |
Interest Rate |  |  |  | 5.00% |  |  |  |  |
Maturity Date |  |  |  | Jan. 15, 2033 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due April 2035 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,000 |  |  | 0 |  |
Interest Rate |  |  |  | 5.40% |  |  |  |  |
Maturity Date |  |  |  | Apr. 01, 2035 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due September 2035 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,500 |  |  | 0 |  |
Interest Rate |  |  |  | 5.40% |  |  |  |  |
Maturity Date |  |  |  | Sep. 15, 2035 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due April 2055 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,000 |  |  | 0 |  |
Interest Rate |  |  |  | 5.95% |  |  |  |  |
Maturity Date |  |  |  | Apr. 01, 2055 |  |  |  |  |
MPLX LP | Senior Notes | Senior Notes Due September 2055 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 1,000 |  |  | 0 |  |
Interest Rate |  |  |  | 6.20% |  |  |  |  |
Maturity Date |  |  |  | Sep. 15, 2055 |  |  |  |  |
MarkWest | Senior Notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 0 |  |  | 11 |  |
Interest Rate |  |  |  | 4.875% |  |  |  |  |
MarkWest | Senior Notes | Senior Notes Due December 2024 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  |  |  |  |  |  |  | 4.875% |
MarkWest | Senior Notes | Senior Notes Due June 2025 [Member] |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  |  |  |  | 4.875% |  |  |  |
ANDX LP [Member] | Senior Notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 31 |  |  | $ 31 |  |
ANDX LP [Member] | Senior Notes | Minimum |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  |  |  | 4.25% |  |  |  |  |
ANDX LP [Member] | Senior Notes | Maximum |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Interest Rate |  |  |  | 5.20% |  |  |  |  |
[1] | See Note 21 for lease information.
[2] | We used a portion of the net proceeds from this offering to fund the Northwind Midstream Acquisition, including the payment of related fees and expenses, and to increase cash and cash equivalents following the recently completed BANGL Acquisition and BANGL Debt Repayment. The remainder of the net proceeds from this offering were used for general partnership purposes.
[3] | On April 9, 2025, MPLX used $1.2 billion of the net proceeds from the issuance of senior notes in March 2025 to redeem all of (i) MPLX’s outstanding $1,189 million aggregate principal amount of 4.875 percent senior notes due June 2025 and (ii) MarkWest’s outstanding $11 million aggregate principal amount of 4.875 percent senior notes due June 2025. The remaining net proceeds from this offering were used for general partnership purposes.

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