Hedging Activities (Effect on Consolidated Financial Statements) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gain (loss) recognized in income	$ 487	$ 204	$ (154)	$ (232)
Foreign Exchange Contracts, Balance Sheet [Member] | Foreign Currency Transaction and Hedge Gain (Loss), Net [Member]
Gain (loss) recognized in income	29	(15)	10	(13)
Translated Earnings Contracts [Member] | Foreign Currency Transaction and Hedge Gain (Loss), Net [Member]
Gain (loss) recognized in income	$ 458	$ 219	$ (164)	$ (219)