Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Four Quarter Rolling Average of Notional Amount of Foreign Exchange Contracts Hedging Foreign Currency Transactions	$ 16,200		$ 15,600
Description of Net Investment Hedge Activity	we have issued approximately €2.95 billion of Euro-denominated debt, which qualifies as a net investment hedge against our investments in European businesses under ASC 815, Derivatives and Hedging. As of March 31, 2016, the net investment hedge is deemed to be effective as defined under ASC 815.
Derivatives designated as hedging instruments, Asset Derivatives	$ 26		4
Derivatives not designated as hedging instruments, Asset Derivatives	70		97
Derivatives designated as hedging instruments, Liability Derivatives	232		428
Derivatives not designated as hedging instruments, Liability Derivatives	79		$ 105
Unrealized Gain (Loss) on Foreign Currency Derivatives, Net, before Tax	159	$ (184)
Loss reclassified from Accumulated other comprehensive loss (gain) into Product Sales (effective portion)	62	57
Foreign Currency Cash Flow Hedge Loss to be Reclassified During Next 12 Months	$ 137
Maximum Length of Time, Foreign Currency Cash Flow Hedge	6 years 7 months 22 days
Gain on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 15	18
Proceeds from Derivative Instrument, Investing Activities	$ 42	$ 569