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Commitments and Contingencies - Other Lawsuits (Details) - Pending Litigation $ in Millions | 3 Months Ended
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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

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