Operations and summary of significant accounting policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) dealers countries distributors	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Operations and Summary of Significant Accounting Policies
Number of countries served by dealers | countries	190
Maximum amortizable period of purchased intangibles (in years)	14 years	14 years
Ownership percentage of investments in companies below which the entity must exercise significant influence in order to be accounted for under the equity method	20.00%
Standard invoice terms, maximum extension period (in years)	1 year	1 year	1 year
Standard invoice terms, amount of extension allowed to receivables | $	$ 406	$ 635	$ 624
Percentage of consolidated sales representing extension to standard invoice terms not more than one year	1.00%	1.00%	1.00%
Period after which collection of future income is considered as not probable (in days)	120 days
Percentage of value of inventories on the LIFO basis to total inventories	60.00%	60.00%
Incremental value of inventory if FIFO method had been in use | $	$ 2,139	$ 2,498
Depreciation on equipment leased to others | $	841	836	$ 872
Consolidated depreciation expense | $	$ 2,707	$ 2,705	$ 2,795
Maximum
Operations and Summary of Significant Accounting Policies
Maximum amortizable period of purchased intangibles (in years)	20 years
Minimum
Operations and Summary of Significant Accounting Policies
Ownership percentage of investments in companies accounted for under the equity method (as a percent)	20.00%
Inside United States
Operations and Summary of Significant Accounting Policies
Number of dealers | dealers	49
Outside the United States
Operations and Summary of Significant Accounting Policies
Number of dealers | dealers	123
Perkins
Operations and Summary of Significant Accounting Policies
Number of distributors | distributors	96
Number of countries where distributors are located | countries	179
Caterpillar Northern Ireland Ltd (F.G. Wilson)
Operations and Summary of Significant Accounting Policies
Number of distributors | distributors	184
Number of countries where distributors are located | countries	145
MaK
Operations and Summary of Significant Accounting Policies
Number of distributors | distributors	20
Number of countries where distributors are located | countries	130