Master Limited Partnerships (Details) - shares	Jul. 30, 2019	Jun. 30, 2019
ANDX
MPC's partnership interest in MLP (in percentage)		64.00%
MPLX
MPC's partnership interest in MLP (in percentage)		64.00%
Subsequent Event | Public
Common units conversion ratio	1.135
Subsequent Event | Nonpublic
Common units conversion ratio	1.0328