Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 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	$ 18,800		$ 18,800		$ 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 June 30, 2017, the net investment hedge is deemed to be effective.
Derivatives designated as hedging instruments, Asset Derivatives	44		$ 44		15
Derivatives not designated as hedging instruments, Asset Derivatives	124		124		155
Derivatives designated as hedging instruments, Liability Derivatives	73		73		196
Derivatives not designated as hedging instruments, Liability Derivatives	69		69		$ 158
Gain recorded in Accumulated other comprehensive loss	66	$ 36	130	$ 195
Loss reclassified from Accumulated other comprehensive loss into Product Sales (effective portion)	5	45	10	107
Foreign Currency Cash Flow Hedge Loss to be Reclassified During Next 12 Months	3		$ 3
Maximum Length of Time, Foreign Currency Cash Flow Hedge			5 years 4 months 26 days
Gain recognized in Other income, net	$ 28	$ 15	$ 40	30
(Payments) receipts from settlements of derivative contracts			$ 294	$ (86)