v3.26.1
Net Income Per Limited Partner Unit - Basic and Diluted Earnings Per Unit (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Earnings Per Share [Abstract]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 1 1 1 1
Net income attributable to MPLX LP(1): [1] $ 1,077 $ 1,048 $ 1,989 $ 2,174
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic 0 0 1 1
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted 0 0 1 1
Net Income (Loss) Available to Common Stockholders, Basic 1,077 1,048 1,988 2,173
Net Income (Loss) Available to Common Stockholders, Diluted $ 1,077 $ 1,048 $ 1,988 $ 2,173
Weighted average units outstanding:        
Common - basic 1,015 1,020 1,015 1,020
Common - diluted 1,015 1,021 1,015 1,020
Per Unit Data (See Note 7)        
Common - basic $ 1.06 $ 1.03 $ 1.96 $ 2.13
Common - diluted $ 1.06 $ 1.03 $ 1.96 $ 2.13
[1] Allocation of net income attributable to MPLX LP assumes all earnings for the period have been distributed based on the distribution priorities applicable to the period.