Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Goodwill and Intangible Assets
Gross amount of amortizable intangible assets	$ 10,900	$ 10,800
Accumulated amortization of intangible assets	6,000	5,700
Change in intangible assets due to foreign currency translation and other adjustments	54
Indefinite-lived intangible assets related to in-process research and development acquired in a business combination	390	$ 419
Estimated annual amortization expense, intangible assets, 2016	580
Estimated annual amortization expense, intangible assets, 2017	560
Estimated annual amortization expense, intangible assets, 2018	520
Estimated annual amortization expense, intangible assets, 2019	490
Estimated annual amortization expense, intangible assets, 2020	480
Non-reportable segment
Goodwill and Intangible Assets
Impairment charges for certain research and development assets	$ 43
Minimum
Goodwill and Intangible Assets
Average amortization period, intangible assets	2 years
Maximum
Goodwill and Intangible Assets
Average amortization period, intangible assets	20 years
Average
Goodwill and Intangible Assets
Average amortization period, intangible assets	14 years