XML 109 R90.htm IDEA: XBRL DOCUMENT v3.10.0.1
Equity (Net Income Allocation) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Equity [Abstract]                      
Net income attributable to MPLX LP $ 434 $ 510 $ 453 $ 421 $ 238 $ 216 $ 190 $ 150 $ 1,818 [1] $ 794 [1] $ 233 [1]
Distributions to preferred unitholders                 (75) (65) (41)
General partner's IDRs and other                   310 191
Net income attributable to MPLX LP available to general and limited partners                   419 1
General partner's two percent GP Interest in net income attributable to MPLX LP                   8 0
General partner's GP Interest in net income attributable to MPLX LP                 $ 0 $ 318 $ 191
[1] Allocation of net income/(loss) attributable to MPLX LP assumes all earnings for the period were distributed based on the current period distribution priorities.