Other (Income) Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Income and Expenses [Abstract]
Gain (Loss) on Sale and Revaluation of Assets	$ 7	$ 33	$ 37	$ 45
Other - net	(11)	8	(2)	3
Other (Income) Expense - Net	(18)	(25)	(39)	(42)
Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	$ (2)	$ 1	$ (10)	$ (4)