| Pay vs Performance Disclosure | 4 Months Ended | 12 Months Ended |
| Apr. 29, 2020 USD ($) | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) |
| Pay vs Performance Disclosure [Table] | | | | |
| Pay vs Performance [Table Text Block] | | Pay Versus Performance SEC rules require us to disclose the following information concerning executive compensation and certain financial performance information about the Company for the periods shown. PAY VERSUS PERFORMANCE TABLE Value of Initial Fixed $100 Investment Based On: Year Summary Compensation Table Total for PEO ($) Compensation Actually Paid to PEO ($) Average Summary Compensation Table Total for Non-PEO NEOs ($) Average Compensation Actually Paid to Non-PEO NEOs ($) Net Income ($ millions) MPC Relative TSR Performance Percentile Total Shareholder Return ($) Peer Group Total Shareholder Return ($) 2022 21,288,532 57,863,217 4,759,899 11,688,458 218.21 153.61 16,050 83.33rd 2021 21,185,206 31,076,741 5,601,203 5,934,676 116.95 90.02 11,001 91.67th 2020 15,534,265 21,219,014 5,628,257 5,101,562 72.64 66.82 (9,977) 90.00th 10,005,700 10,070,251 | | |
| Company Selected Measure Name | | MPC Relative TSR Performance Percentile | | |
| Named Executive Officers, Footnote [Text Block] | | • 2022: Maryann T. Mannen, Suzanne Gagle, Timothy J. Aydt, Gregory S. Floerke and Raymond L. Brooks. • 2021: Maryann T. Mannen, Raymond L. Brooks, Suzanne Gagle, Brian C. Davis, Donald C. Templin and Timothy T. Griffith. • 2020: Donald C. Templin, Timothy T. Griffith, Raymond L. Brooks and Suzanne Gagle. | | |
| Peer Group Issuers, Footnote [Text Block] | | Peer Group Total Shareholder Return is shown for the S&P 500 Oil & Gas Refining & Marketing Sub-Industry Index, which is the same peer group used for the Stock Return Performance Graph included in our 2022 Annual Report. | | |
| PEO Total Compensation Amount | $ 10,005,700 | $ 21,288,532 | $ 21,185,206 | $ 15,534,265 |
| PEO Actually Paid Compensation Amount | 10,070,251 | $ 57,863,217 | 31,076,741 | 21,219,014 |
| Adjustment To PEO Compensation, Footnote [Text Block] | | PEO SCT TOTAL TO CAP TOTAL RECONCILIATION Additions to SCT Total Year SCT Total ($) Deductions from SCT Total ($) Pension Service Cost ($) Change in Value of Equity Awards as Summarized Below CAP Total ($) 2022 21,288,532 14,521,516 374,531 50,721,670 57,863,217 2021 21,185,206 14,636,291 292,772 24,235,054 31,076,741 2020 * 15,534,265 10,532,443 234,235 15,982,957 21,219,014 10,005,700 6,000,009 — 6,064,560 10,070,251 * Includes Mr. Hennigan (top row) and Mr. Heminger (bottom row). | | |
| Non-PEO NEO Average Total Compensation Amount | | $ 4,759,899 | 5,601,203 | 5,628,257 |
| Non-PEO NEO Average Compensation Actually Paid Amount | | $ 11,688,458 | 5,934,676 | 5,101,562 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | | NON-PEO NEO (AVERAGE) SCT TOTAL TO CAP TOTAL RECONCILIATION Additions to SCT Total Year SCT Total ($) Deductions from SCT Total ($) Pension Service Cost ($) Change in Value of Equity Awards as Summarized Below CAP Total ($) 2022 4,759,899 2,890,901 94,246 9,725,214 11,688,458 2021 5,601,203 4,130,399 99,299 4,364,573 5,934,676 2020 5,628,257 3,309,326 164,855 2,617,776 5,101,562 | | |
| Equity Valuation Assumption Difference, Footnote [Text Block] | | Additions to SCT Total reflect the value of equity calculated in accordance with SEC methodology for determining CAP for each year shown. While stock options at grant were determined using a Black-Scholes valuation, the valuation of stock options at either year-end or vesting date was determined using a lattice model. The equity components of CAP are further detailed in the supplemental tables below. | | |
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | | | | |
| Compensation Actually Paid vs. Net Income [Text Block] | | | | |
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | | | | |
| Total Shareholder Return Vs Peer Group [Text Block] | | | | |
| Tabular List [Table Text Block] | | FINANCIAL PERFORMANCE MEASURES USED TO LINK EXECUTIVE COMPENSATION TO MPC PERFORMANCE MPC Relative TSR Performance Percentile MPC TSR MPLX Total Unitholder Return* MPC Adjusted EBITDA * This measure is calculated pursuant to SEC Regulation S-K, Item 402(v)(2)(iv), and is different than the TUR metric used for the MPLX performance units, discussed in more detail beginning on page 46 | | |
| Total Shareholder Return Amount | | $ 218.21 | 116.95 | 72.64 |
| Peer Group Total Shareholder Return Amount | | 153.61 | 90.02 | 66.82 |
| Net Income (Loss) | | $ 16,050,000,000 | $ 11,001,000,000 | $ (9,977,000,000) |
| Company Selected Measure Amount | | 83.33 | 91.67 | 90 |
| PEO Name | | •2022 and 2021: Michael J. Hennigan.•2020: Michael J. Hennigan (top row), who was promoted to the CEO role effective March 17, 2020, and Gary R. Heminger (bottom row), who stepped down from the CEO role on that date but continued to serve in his role as Chairman of the Board through April 29, 2020. | | |
| Measure [Axis]: 1 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | | MPC Relative TSR Performance Percentile | | |
| Measure [Axis]: 2 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | | MPC TSR | | |
| Measure [Axis]: 3 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | | MPLX Total Unitholder Return* | | |
| Measure [Axis]: 4 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | | MPC Adjusted EBITDA | | |
| PEO [Member] | Change in pension value and grant date fair value of equity-based awards granted [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 6,000,009 | $ 14,521,516 | $ 14,636,291 | $ 10,532,443 |
| PEO [Member] | Pension service cost [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | 0 | 374,531 | 292,772 | 234,235 |
| PEO [Member] | Change in value of equity awards [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | $ 6,064,560 | 50,721,670 | 24,235,054 | 15,982,957 |
| Non-PEO NEO [Member] | Change in pension value and grant date fair value of equity-based awards granted [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | | 2,890,901 | 4,130,399 | 3,309,326 |
| Non-PEO NEO [Member] | Pension service cost [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | | 94,246 | 99,299 | 164,855 |
| Non-PEO NEO [Member] | Change in value of equity awards [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | | $ 9,725,214 | $ 4,364,573 | $ 2,617,776 |
