MPLX LP - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified |
1 Months Ended | 8 Months Ended | 1 Months Ended | 6 Months Ended | ||||
---|---|---|---|---|---|---|---|---|
Jun. 30, 2013
MPLX LP [Member]
Noncontrolling Interests [Member]
|
Oct. 31, 2012
MPLX LP [Member]
IPO [Member]
|
Jun. 30, 2013
MPLX LP [Member]
General Partner [Member]
|
Jun. 30, 2013
MPLX LP [Member]
General Partner and Limited Partner [Member]
|
Jun. 30, 2013
Butane Cavern [Member]
MPLX LP [Member]
|
May 01, 2013
MPLX Pipe Line Holdings LP [Member]
|
May 01, 2013
MPLX Pipe Line Holdings LP [Member]
MPLX LP [Member]
|
Apr. 30, 2013
MPLX Pipe Line Holdings LP [Member]
MPLX LP [Member]
General Partner [Member]
|
|
Noncontrolling Interest [Line Items] | ||||||||
Ownership Percentage | 100.00% | 44.00% | 56.00% | 51.00% | ||||
Sale of additional ownership interest percentage | 5.00% | |||||||
Proceeds from sale of ownership interest | $ 100 | |||||||
Initial public offering of common units (in number of common units) | 19,895,000 | |||||||
Initial public offering date of MPLX LP | October 31, 2012 | |||||||
Net proceeds to MPLX from the sale of the units | $ 407 | |||||||
MPC's partnership interest in MPLX (in percentage) | 2.00% | 73.60% | ||||||
Public ownership interest percentage in MPLX | 26.40% |