v3.24.1.u1
Credit Agreement (Detail) - USD ($)
$ in Millions
Jul. 07, 2022
Mar. 31, 2024
Dec. 31, 2023
Debt Instrument [Line Items]      
Long-term Line of Credit   $ 0 $ 0
MPLX Revolving Credit Facility due June 2027      
Debt Instrument [Line Items]      
Line of Credit Facility, Maximum Borrowing Capacity $ 2,000    
Letter of Credit, Issuing Capacity $ 150    
Debt Instrument, Description of Variable Rate Basis Adjusted Term SOFR or the Alternate Base Rate, both as defined in the MPLX Credit Agreement, plus an applicable margin.