Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Four Quarter Rolling Average of Notional Amount of Foreign Exchange Contracts Hedging Foreign Currency Transactions	$ 18,500		$ 18,300
Description of Net Investment Hedge Activity	we have issued approximately €2.95 billion of euro-denominated long-term debt and €500 million of outstanding euro-denominated commercial paper borrowings, which qualify as a net investment hedge against our investments in European businesses. As of March 31, 2017, the net investment hedge is deemed to be effective.
Derivatives designated as hedging instruments, Asset Derivatives	$ 22		15
Derivatives not designated as hedging instruments, Asset Derivatives	84		155
Derivatives designated as hedging instruments, Liability Derivatives	128		196
Derivatives not designated as hedging instruments, Liability Derivatives	113		$ 158
(Loss) gain recorded in Accumulated other comprehensive loss	64	$ 159
Loss reclassified from Accumulated other comprehensive loss into Product Sales (effective portion)	5	62
Foreign Currency Cash Flow Hedge Loss to be Reclassified During Next 12 Months	$ 25
Maximum Length of Time, Foreign Currency Cash Flow Hedge	5 years 7 months 20 days
Gain recognized in Other income, net	$ 12	15
(Payments) receipts from settlements of derivative contracts	$ 113	$ (42)