Master Limited Partnership (Details)	Mar. 31, 2020
MPLX \| Marathon Petroleum Corporation [Member]
MPC's partnership interest in MLP (in percentage)	63.00%

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant