Nature of Operations and Basis of Presentation - Components of Other (Income) Expense, Net (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other expense (income), net	$ 103	$ (4)
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other components of net periodic benefit cost	103	(8)
Net loss from investments	0	4
Other expense (income), net	$ 103	$ (4)