Goodwill and intangible assets (Identifiable Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Finite-lived intangible assets:
Gross carrying amount	$ 18,344	$ 18,264
Accumulated amortization	(10,121)	(8,744)
Other intangible assets, net	8,223	9,520
Indefinite-lived intangible assets:
Identifiable intangible assets	18,730	19,023
Accumulated amortization	(10,121)	(8,744)
Identifiable intangible assets, net	8,609	10,279
IPR&D [Member]
Indefinite-lived intangible assets:
Indefinite-lived intangible assets	386	759
Developed product technology rights [Member]
Finite-lived intangible assets:
Gross carrying amount	12,589	12,534
Accumulated amortization	(6,796)	(5,947)
Other intangible assets, net	5,793	6,587
Licensing rights [Member]
Finite-lived intangible assets:
Gross carrying amount	3,275	3,275
Accumulated amortization	(1,601)	(1,300)
Other intangible assets, net	1,674	1,975
Marketing-related rights [Member]
Finite-lived intangible assets:
Gross carrying amount	1,319	1,333
Accumulated amortization	(920)	(793)
Other intangible assets, net	399	540
R&D technology rights [Member]
Finite-lived intangible assets:
Gross carrying amount	1,161	1,122
Accumulated amortization	(804)	(704)
Other intangible assets, net	$ 357	$ 418