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
Mar. 31, 2026
Mar. 31, 2025
Earnings Per Share [Abstract]    
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 1 1
Net income attributable to MPLX LP(1): [1] $ 912 $ 1,126
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic 1 0
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted 1 0
Net Income (Loss) Available to Common Stockholders, Basic 911 1,126
Net Income (Loss) Available to Common Stockholders, Diluted $ 911 $ 1,126
Weighted average units outstanding:    
Common - basic 1,015 1,020
Common - diluted 1,015 1,020
Per Unit Data (See Note 7)    
Common - basic $ 0.90 $ 1.10
Common - diluted $ 0.90 $ 1.10
[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.