Hedging Activities (Effect on Consolidated Financial Statements) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Gain (loss) recognized in income	$ 240	$ 19	$ 85	$ (212)
Foreign Exchange Contracts, Balance Sheet [Member] | Foreign Currency Transaction and Hedge Gain (Loss), Net [Member]
Gain (loss) recognized in income	10	(7)	19	(19)
Translated Earnings Contracts [Member] | Foreign Currency Transaction and Hedge Gain (Loss), Net [Member]
Gain (loss) recognized in income	$ 230	$ 26	$ 66	$ (193)