Commitments and Contingencies - Other Lawsuits (Details) - Pending Litigation $ in Millions |
3 Months Ended |
|---|---|
|
Mar. 31, 2018
USD ($)
| |
| Construction Work at MarkWest Processing and Fractionation Complexes | Minimum | |
| Loss Contingencies [Line Items] | |
| Damages sought | $ 40 |
| Construction Work at MarkWest Processing and Fractionation Complexes | Minimum | MPLX LP | |
| Loss Contingencies [Line Items] | |
| Damages sought | $ 10 |
| Emergency Pricing And Consumer Protection Laws | |
| Loss Contingencies [Line Items] | |
| Plaintiff | Commonwealth of Kentucky |
| Damages sought | $ 89 |
| Loss contingency, period of occurrence | during September and October 2005 |