Operations and summary of significant accounting policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) dealers countries distributors	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Operations and summary of significant accounting policies
Number of countries served by dealers	191
Percentage of value of inventories on the LIFO basis to total inventories	60.00%	65.00%
Maximum amortizable period of purchased intangibles (in years)	14 years	14 years
Incremental value of inventory if FIFO method had been in use | $	$ 2,086	$ 2,009
Consolidated depreciation expense | $	2,253	2,435	$ 2,555
Depreciation on equipment leased to others | $	$ 813	$ 819	$ 810
Inside United States
Operations and summary of significant accounting policies
Number of dealers | dealers	46
Countries Outside United States
Operations and summary of significant accounting policies
Number of dealers | dealers	119
Perkins
Operations and summary of significant accounting policies
Number of countries where distributors are located	178
Number of distributors | distributors	67
FG Wilson
Operations and summary of significant accounting policies
Number of countries where distributors are located	109
Number of distributors | distributors	150
MaK
Operations and summary of significant accounting policies
Number of countries where distributors are located	130
Number of distributors | distributors	20
Maximum
Operations and summary of significant accounting policies
Maximum amortizable period of purchased intangibles (in years)	20 years