MPLX LP (Detail) - MPLX LP |
Mar. 31, 2018 |
|---|---|
| Noncontrolling Interest [Line Items] | |
| Ownership percentage of general partner interest | 100.00% |
| Public's ownership interest in MPLX (in percentage) | 36.40% |
| General Partner and Limited Partner | |
| Noncontrolling Interest [Line Items] | |
| MPC's partnership interest in MPLX (in percentage) | 63.60% |