Debt - MPLX 364-Day Term Loan (Details) - MPLX LP - MPLX 364-day term loan - USD ($) $ in Billions |
Feb. 08, 2018 |
Feb. 01, 2018 |
Jan. 02, 2018 |
|---|---|---|---|
| Debt Instrument [Line Items] | |||
| Maximum borrowing capacity | $ 4.1 | $ 4.1 | |
| Debt instrument, term | 364 days | 364 days | |
| Borrowings | $ 4.1 | ||
| Repayments of short-term debt | $ 4.1 |