Goodwill and other intangible assets (Identifiable Intangible Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	$ 31,939	$ 31,991
Accumulated amortization	(13,316)	(12,632)
Other intangible assets, net	18,623	19,359
Gross carrying amount	31,969	32,045
Accumulated amortization	(13,316)	(12,632)
Intangible assets, net	18,653	19,413
In-process Research and Development [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	30	54
Developed-Product-Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	25,549	25,575
Accumulated amortization	(8,876)	(8,322)
Other intangible assets, net	16,673	17,253
Licensing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	3,746	3,761
Accumulated amortization	(2,494)	(2,398)
Other intangible assets, net	1,252	1,363
Marketing-Related Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	1,375	1,382
Accumulated amortization	(979)	(965)
Other intangible assets, net	396	417
Research and Development Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	1,269	1,273
Accumulated amortization	(967)	(947)
Other intangible assets, net	$ 302	$ 326