Other Income and Expense - Other Expense (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2020	Jun. 30, 2019
Schedule of other expense [Line Items]
Gain (Loss) on Disposition of Assets					$ 40	$ (16)
Other Nonoperating Expense	$ 158		$ 0		202	0
Other Expenses	3		14		7	26
Other Expense [Member]
Schedule of other expense [Line Items]
Gain (Loss) on Disposition of Assets	1	[1]	9	[1]	2	14
Defined Benefit Plan, Other Cost (Credit)	1		5		1	9
Other Nonoperating Expense	1		0		4	3
Other Expenses	$ 3		$ 14		$ 7	$ 26

[1] Primarily associated with the gain on sale of Redondo Beach land at Southland. See Note 18—Held-for-Sale and Dispositions for further information.