Other (Income) Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gain (Loss) on Sale and Revaluation of Assets	$ 6	$ 35	$ 12	$ 51
Other (income) expense - net	4	44	(5)	62
Other (Income) Expense - Net	(2)	9	(17)	11
Other (Income) Expense - Net [Member]
Defined benefit plan net periodic benefit cost other than service cost	$ 2	$ (11)	$ 5	$ (20)