Property, plant and equipment (Schedule) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Land	$ 283	$ 295
Buildings and improvements	3,507	3,640
Manufacturing equipment	2,372	2,275
Laboratory equipment	1,179	1,092
Other	4,404	4,380
Construction in progress	834	745
Property, plant and equipment, gross	12,579	12,427
Less accumulated depreciation and amortization	(7,590)	(7,466)
Property, plant and equipment, net	4,989	4,961
Depreciation and amortization charges associated with property, plant and equipment	$ 604	$ 619	$ 727
Buildings and improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	10 years
Buildings and improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	40 years
Manufacturing equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	8 years
Manufacturing equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	12 years
Laboratory equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	8 years
Laboratory equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	12 years
Other [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	3 years
Other [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	15 years