Leases Lessor Lease Revenues (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	[2]
MPC
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	[1]	$ 186	$ 279
Sales-type Lease, Interest Income		38
Sales-type Lease, Variable Lease Income		0
Third Party [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	[1]	$ 63	$ 65

[1] These amounts are presented net of executory costs.

[2] Financial information for the first quarter of 2019 has been retrospectively adjusted for the acquisition of ANDX. See Notes 1 and 3.