Property, plant and equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Property, plant and equipment
Total property, plant and equipment, at cost	$ 29,217		$ 29,781
Less: Accumulated depreciation	(16,313)		(16,207)
Property, plant and equipment - net	12,904	$ 13,548	13,574
Land
Property, plant and equipment
Total property, plant and equipment, at cost	664		671
Buildings and land improvements
Property, plant and equipment
Total property, plant and equipment, at cost	6,710		6,977
Machinery, equipment and other
Property, plant and equipment
Total property, plant and equipment, at cost	13,287		13,733
Software
Property, plant and equipment
Total property, plant and equipment, at cost	1,728		1,703
Equipment leased to others
Property, plant and equipment
Total property, plant and equipment, at cost	6,208		6,015
Construction-in-process
Property, plant and equipment
Total property, plant and equipment, at cost	$ 620		$ 682
Minimum | Buildings and land improvements
Property, plant and equipment
Useful Lives (Years)	20 years
Minimum | Machinery, equipment and other
Property, plant and equipment
Useful Lives (Years)	2 years
Minimum | Software
Property, plant and equipment
Useful Lives (Years)	3 years
Minimum | Equipment leased to others
Property, plant and equipment
Useful Lives (Years)	1 year
Maximum | Buildings and land improvements
Property, plant and equipment
Useful Lives (Years)	45 years
Maximum | Machinery, equipment and other
Property, plant and equipment
Useful Lives (Years)	10 years
Maximum | Software
Property, plant and equipment
Useful Lives (Years)	7 years
Maximum | Equipment leased to others
Property, plant and equipment
Useful Lives (Years)	7 years