Financial Instruments (Narrative) (Details) € in Millions, $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 EUR (€)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Four Quarter Rolling Average Of Notional Amount Of Foreign Exchange Contracts Hedging Foreign Currency Transactions	$ 19,100	$ 18,300
Derivatives designated as hedging instruments - assets	178	15
Derivatives not designated as hedging instruments - assets	75	155
Derivatives designated as hedging instruments - liabilities	18	196
Derivatives not designated as hedging instruments - liabilities	60	158
Hedging Liabilities, Noncurrent \| €				€ 3,700
Gain recorded in Accumulated other comprehensive loss	347	75
(Gain) loss reclassified from Accumulated other comprehensive loss into Product sales (effective portion)	(39)	171
Foreign Currency Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months	$ (66)
Maximum Length of Time, Foreign Currency Cash Flow Hedge	3 years 11 months 21 days
Gain recognized in Other income, net	$ 77	56
Payments for (Proceeds from) Derivative Instrument, Investing Activities	$ 317	$ (249)	$ (160)

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Fair value as of the balance sheet date of all foreign currency derivative assets designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(1)
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The amount of net gains or losses on foreign currency cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

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The estimated net amount of unrealized gains or losses on foreign currency cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

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-Publisher FASB
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Fair value as of the balance sheet date of all foreign currency derivative liabilities designated as cash flow hedging instruments.

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Fair value as of the balance sheet date of all foreign currency derivative assets not designated as hedging instruments.

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Fair value as of the balance sheet date of all foreign currency derivative liabilities not designated as hedging instruments.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of foreign currency derivatives not designated as hedging instruments.

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Fair value of liability arising from a financial instrument or contract used to mitigate a specified risk (hedge), expected to be settled after one year or beyond the normal operating cycle, if longer.

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Maximum period of time the entity is hedging its exposure to variability in future cash flows for forecasted transactions, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Excludes forecasted transactions related to payment of variable interest on existing financial instruments.

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The net cash outflow or inflow from derivative instruments during the period, which are classified as investing activities, excluding those designated as hedging instruments.

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Amount of net unrealized gain (loss) related to the change in fair value of foreign currency exchange rate derivatives designated as cash flow hedging instruments. Recorded in accumulated other comprehensive income to the extent that the cash flow hedge is determined to be effective.

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Four quarter rolling average notional amount of all foreign currency derivatives designated as hedging instruments in cash flow hedges. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

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