Other Income and Expense - Other Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule of other expense [Line Items]
Gain (Loss) on Disposition of Assets			$ (16)	$ (2)
Other Expenses	$ 14	$ 4	26	13
Other Expense [Member]
Schedule of other expense [Line Items]
Gain (Loss) on Disposition of Assets	9	3	14	5
Defined Benefit Plan, Other Cost (Credit)	5	1	9	6
Other Nonoperating Expense	0	0	3	2
Other Expenses	$ 14	$ 4	$ 26	$ 13