Financial Instruments (Pre-Tax Effect of Foreign Exchange Contracts Designated as Other Derivatives) (Details) - Not Designated as Hedging Instrument [Member] - Foreign Exchange Contract [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in Earnings	$ (60)	$ (24)	$ (1)
Interest expense, net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in Earnings	$ (60)	$ (24)	$ (1)