Consolidated Balance Sheets - USD ($) $ in Millions		Jun. 30, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents		$ 67	$ 15
Receivables, net		562	593
Current Assets, Related Parties		594	656
Inventories		115	110
Other current assets		48	110
Total current assets		1,386	1,484
Equity method investments		4,065	5,275
Property, plant and equipment, net		21,758	22,145
Intangibles, net		1,023	1,270
Goodwill		7,722	9,536
Operating Lease, Right-of-Use Asset		341	365
Other Assets, Related Parties, Noncurrent		676	303
Other noncurrent assets		51	52
Total assets		37,022	40,430
Current liabilities:
Accounts payable		145	242
Accrued Liabilities, Current		138	187
Current Liabilities, Related Parties		372	1,008
Accrued Property Plant and Equipment Current		154	283
Accrued interest payable		207	210
Operating Lease, Liability, Current		69	66
Other current liabilities		143	136
Total current liabilities		1,228	2,132
Long-term deferred revenue		261	217
Liabilities, Related Parties, Noncurrent		287	290
Long-term debt		20,556	19,704
Deferred income taxes		11	12
Operating Lease, Liability, Noncurrent		274	302
Deferred credits and other liabilities		175	192
Total liabilities		22,792	22,849
Commitments and contingencies (see Note 21)
Series A preferred units		968	968
Equity
Total MPLX LP partners’ capital		13,015	16,364
Accumulated other comprehensive loss	[1]	(16)	(15)
Noncontrolling interests		247	249
Total equity		13,262	16,613
Total liabilities, preferred units and equity		37,022	40,430
MPC
Assets
Other current assets		1	0
Operating Lease, Right-of-Use Asset		231	232
Current liabilities:
Operating Lease, Liability, Current		1	1
Operating Lease, Liability, Noncurrent		230	230
Series B Preferred Stock [Member]
Equity
Total MPLX LP partners’ capital		611	611
Limited Partners Common Units | Public
Equity
Total MPLX LP partners’ capital		9,469	10,800
Total equity		9,469	10,800
Limited Partners Common Units | MPC
Equity
Total MPLX LP partners’ capital		2,951	4,968
Total equity		2,951	4,968
LOOP and Explorer
Equity
Accumulated other comprehensive loss		(16)	(15)
Retained Earnings [Member] | MPC
Equity
Total equity		$ 0	$ 0

[1] These components of “Accumulated other comprehensive loss” are included in the computation of net periodic benefit cost by LOOP and Explorer and are therefore included on the Consolidated Statements of Income under the caption “Income/(loss) from equity method investments.”