MPLX LP - Dropdowns to MPLX and GP/IDR Exchange(Details) - MPLX LP - USD ($) shares in Thousands, $ in Millions |
Feb. 01, 2018 |
Jan. 02, 2018 |
Sep. 01, 2017 |
Mar. 01, 2017 |
|---|---|---|---|---|
| MPLX 364-day term loan | ||||
| Noncontrolling Interest [Line Items] | ||||
| Maximum borrowing capacity | $ 4,100 | $ 4,100 | ||
| Debt instrument, term | 364 days | 364 days | ||
| Cash and Cash Equivalents | ||||
| Noncontrolling Interest [Line Items] | ||||
| Payments to acquire business, gross | $ 4,100 | $ 420 | $ 1,500 | |
| Limited Partner | ||||
| Noncontrolling Interest [Line Items] | ||||
| Units issued, number of units | 112,000 | 19,000 | 13,000 | |
| Conversion of stock, shares issued | 275,000 | |||
| General Partner | ||||
| Noncontrolling Interest [Line Items] | ||||
| Units issued, number of units | 2,000 | 378 | 264 |