Leases Lessor Lease Revenues (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Lessor, Lease, Description [Line Items]
Sales-type Lease, Selling Profit (Loss)			$ 209
MPC
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	[1]	$ 208		$ 248	$ 589	$ 773
Sales-type Lease, Interest Income		37		3	113	3
Sales-type Lease, Variable Lease Income		1		1	1	1
Third Party [Member]
Lessor, Lease, Description [Line Items]
Operating Lease, Lease Income	[1]	70		63	199	196
Sales-type Lease, Selling Profit (Loss)		0			0
Sales-type Lease, Interest Income		0			0
Sales-type Lease, Variable Lease Income		0			0
MPC
Lessor, Lease, Description [Line Items]
Sales-type Lease, Selling Profit (Loss)		$ 0		$ 0	$ 0	$ 0

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