Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Sales-type lease revenue		$ 33	$ 0	$ 67	$ 0
Sales-type lease revenue - related parties		125	114	250	225
Income from equity method investments		145	111	279	210
Total revenues and other income		2,690	2,940	5,403	5,550
Costs and Expenses, Related Party		357	351	718	670
Depreciation and amortization	[1]	310	310	606	623
General and administrative expenses		89	82	178	160
Other taxes		28	33	58	67
Total costs and expenses		1,515	1,823	3,032	3,373
Operating Income (Loss)		1,175	1,117	2,371	2,177
Interest expense, net of amounts capitalized		226	212	450	410
Other financial costs		7	20	26	40
Income before income taxes		942	884	1,895	1,722
Provision for income taxes		0	0	1	5
Net income		942	884	1,894	1,717
Less: Net income attributable to noncontrolling interests		9	9	18	17
Net income attributable to MPLX LP	[2]	933	875	1,876	1,700
Limited partners' interest in net income attributable to MPLX LP		$ 910	$ 844	$ 1,825	$ 1,637
Net income attributable to MPLX LP per limited partner unit:
Common - basic		$ 0.91	$ 0.83	$ 1.81	$ 1.61
Common - diluted		$ 0.91	$ 0.83	$ 1.81	$ 1.61
Weighted average limited partner units outstanding:
Common - basic		1,001	1,012	1,001	1,013
Common - diluted		1,001	1,012	1,001	1,014
Nonrelated Party [Member]
Rental income		$ 59	$ 102	$ 120	$ 193
Other Income		18	6	21	(11)
Rental cost of sales		20	42	40	79
Related Party [Member]
Rental income		203	198	405	363
Other Income		31	27	58	54
Rental cost of sales		9	19	16	34
General and administrative expenses		61	58	125	113
Related-party interest and other financial costs		0	1	0	5
Service [Member]
Revenue from Contract with Customer, Excluding Assessed Tax - third and related parties		635	577	1,240	1,131
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties		971	938	1,924	1,853
Service, Other [Member]
Revenue from Contract with Customer, Excluding Assessed Tax - third and related parties		60	118	139	241
Product [Member]
Revenue from Contract with Customer, Excluding Assessed Tax - third and related parties		376	698	796	1,195
Revenue from Contract with Customer, Excluding Assessed Tax, Related Parties		34	51	104	96
Oil and Gas, Refining and Marketing [Member]
Cost of Goods and Services Sold		348	323	656	610
Natural Gas, Midstream [Member]
Cost of Goods and Services Sold		354	663	760	1,130
Series A Preferred Stock [Member]
Net income attributable to MPLX LP	[2]	27	25	54	48
Dividends, Preferred Stock		23	21	46	42
Series B Preferred Stock [Member]
Net income attributable to MPLX LP	[2]		10	5	21
Dividends, Preferred Stock		0	10	5	21
Common Stock [Member]
Net income attributable to MPLX LP	[2]	$ 906	$ 840	$ 1,817	$ 1,631

[1] Depreciation and amortization attributable to L&S was $140 million and $269 million for the three and six months ended June 30, 2023, respectively, and $129 million and $259 million for the three and six months ended June 30, 2022, respectively. Depreciation and amortization attributable to G&P was $170 million and $337 million for the three and six months ended June 30, 2023, respectively, and $181 million and $364 million for the three and six months ended June 30, 2022, respectively.

[2] Allocation of net income attributable to MPLX LP assumes all earnings for the period had been distributed based on the distribution priorities applicable to the period.