Hedging Activities (Summary of Notional Amounts and Respective Fair Values of Derivative Financial Instruments) (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Notional amount		$ 14,911	$ 15,718
Asset derivatives, fair value		148	265
Liability derivatives, fair value		(442)	(374)
Foreign Exchange Contracts [Member] | Designated as Hedging Instrument [Member]
Notional amount	[1]	391	294
Foreign Exchange Contracts [Member] | Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Asset derivatives, fair value	[1]	4	20
Foreign Exchange Contracts [Member] | Designated as Hedging Instrument [Member] | Other Assets [Member]
Asset derivatives, fair value	[1]	2	1
Foreign Exchange Contracts [Member] | Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Liability derivatives, fair value	[1]	(2)
Foreign Exchange Contracts [Member] | Not Designated as Hedging Instrument [Member]
Notional amount		900	599
Foreign Exchange Contracts [Member] | Not Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Asset derivatives, fair value		5	2
Foreign Exchange Contracts [Member] | Not Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Liability derivatives, fair value		(7)	(7)
Interest Rate Contracts [Member] | Designated as Hedging Instrument [Member]
Notional amount			550
Liability derivatives, fair value			(8)
Translated Earnings Contracts [Member] | Not Designated as Hedging Instrument [Member]
Notional amount		13,620	14,275
Translated Earnings Contracts [Member] | Not Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Asset derivatives, fair value		94	176
Translated Earnings Contracts [Member] | Not Designated as Hedging Instrument [Member] | Other Assets [Member]
Asset derivatives, fair value		43	66
Translated Earnings Contracts [Member] | Not Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Liability derivatives, fair value		(47)	(34)
Translated Earnings Contracts [Member] | Not Designated as Hedging Instrument [Member] | Other Liabilities [Member]
Liability derivatives, fair value		$ (386)	$ (325)

[1] Cash flow hedges with a typical duration of 24 months or less.