Goodwill and other intangible assets (Identifiable Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	$ 32,001	$ 32,018
Accumulated amortization	(17,372)	(15,461)
Other intangible assets, net	14,629	16,557
Gross carrying amount	32,031	32,048
Accumulated amortization	(17,372)	(15,461)
Intangible assets, net	14,659	16,587
In-process Research and Development [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	30	30
Developed-Product-Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	25,575	25,591
Accumulated amortization	(12,222)	(10,564)
Other intangible assets, net	13,353	15,027
Licensing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	3,766	3,743
Accumulated amortization	(2,931)	(2,791)
Other intangible assets, net	835	952
Marketing-Related Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	1,362	1,367
Accumulated amortization	(1,099)	(1,041)
Other intangible assets, net	263	326
Research and Development Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amounts	1,298	1,317
Accumulated amortization	(1,120)	(1,065)
Other intangible assets, net	$ 178	$ 252