Goodwill and other intangible assets (Idenfitiable Intangible Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Gross carrying amount	$ 19,103	$ 18,920
Accumulated amortization	(7,655)	(7,279)
Intangible assets, net	11,448	11,641
Finite-lived intangible assets:
Gross carrying amount	18,087	17,905
Accumulated amortization	(7,655)	(7,279)
Intangible assets, net	10,432	10,626
IPR&D [Member]
Indefinite-lived intangible assets:
Indefinite-lived intangible assets	1,016	1,015
Developed Product Technology Rights [Member]
Finite-lived intangible assets:
Gross carrying amount	12,320	12,310
Accumulated amortization	(5,235)	(4,996)
Intangible assets, net	7,085	7,314
Licensing Rights [Member]
Finite-lived intangible assets:
Gross carrying amount	3,275	3,275
Accumulated amortization	(1,073)	(998)
Intangible assets, net	2,202	2,277
Research and Development Technology Rights [Member]
Finite-lived intangible assets:
Gross carrying amount	1,142	1,134
Accumulated amortization	(658)	(635)
Intangible assets, net	484	499
Marketing-related Rights [Member]
Finite-lived intangible assets:
Gross carrying amount	1,350	1,186
Accumulated amortization	(689)	(650)
Intangible assets, net	$ 661	$ 536