Segment Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) group_presidents segments dealers	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information
Number of group presidents | group_presidents			4
Number of operating segments | segments			6
Useful life to amortize goodwill for segment assets			20 years
Reportable Segments
Total sales and revenues	$ 13,510	$ 11,413	$ 40,380	$ 32,566
Depreciation and amortization	698	723	2,065	2,153
Consolidated profit before taxes	2,135	1,523	6,455	2,971
Segment assets	78,209		78,209		$ 76,962
Capital expenditures	601	513	2,129	1,637
Revenues earned from Machinery, Energy & Transportation	122	93	$ 345	281
All Other operating segments
Segment Reporting Information
Number of group presidents | group_presidents			1
Number of smaller operating segments led by Group President | group_presidents			2
Number of wholly-owned dealers involved in segment reallocation | dealers			1
Reportable Segments
Total sales and revenues		56		126
Depreciation and amortization	55	52	$ 170	162
Consolidated profit before taxes	(10)	5	70	(28)
Segment assets	1,273		1,273		1,312
Capital expenditures	63	26	101	71
Reportable Segments Including Intersegment Eliminations
Reportable Segments
Total sales and revenues	14,721	12,454	$ 43,970	35,550
Reportable Segments
Segment Reporting Information
Number of operating segments led by Group Presidents | segments			3
Number of operating segments led by Group President responsible for corporate services | segments			1
Reportable Segments
Number of reportable segments | segments			4
Total sales and revenues	13,614	11,459	$ 40,661	32,742
Depreciation and amortization	579	597	1,719	1,788
Consolidated profit before taxes	2,646	2,041	7,867	5,447
Segment assets	55,541		55,541		53,698
Capital expenditures	566	512	1,928	1,538
Intersegment sales and revenues
Reportable Segments
Total sales and revenues	1,107	995	3,309	2,808
Machinery, Energy & Transportation | Reportable Segments Including Intersegment Eliminations
Reportable Segments
Total sales and revenues	13,876	11,680	41,503	33,240
Machinery, Energy & Transportation | Reportable Segments
Reportable Segments
Total sales and revenues	12,769	10,685	38,194	30,432
Depreciation and amortization	367	393	1,092	1,172
Consolidated profit before taxes	2,445	1,856	7,391	4,888
Segment assets	19,812		19,812		18,805
Capital expenditures	268	204	736	520
Machinery, Energy & Transportation | Intersegment sales and revenues
Reportable Segments
Total sales and revenues	1,107	995	3,309	2,808
Construction Industries | Reportable Segments Including Intersegment Eliminations
Reportable Segments
Total sales and revenues	5,683	4,886	17,532	13,945
Construction Industries | Reportable Segments
Reportable Segments
Total sales and revenues	5,654	4,854	17,450	13,875
Depreciation and amortization	93	99	272	301
Consolidated profit before taxes	1,058	884	3,329	2,418
Segment assets	5,071		5,071		4,838
Capital expenditures	58	50	162	107
Construction Industries | Intersegment sales and revenues
Reportable Segments
Total sales and revenues	29	32	82	70
Resource Industries | Reportable Segments Including Intersegment Eliminations
Reportable Segments
Total sales and revenues	2,638	1,956	7,473	5,553
Resource Industries | Reportable Segments
Reportable Segments
Total sales and revenues	2,538	1,870	7,177	5,299
Depreciation and amortization	115	129	346	386
Consolidated profit before taxes	414	229	1,203	488
Segment assets	6,439		6,439		6,403
Capital expenditures	49	41	111	93
Resource Industries | Intersegment sales and revenues
Reportable Segments
Total sales and revenues	100	86	296	254
Energy & Transportation | Reportable Segments Including Intersegment Eliminations
Reportable Segments
Total sales and revenues	5,555	4,838	16,498	13,742
Energy & Transportation | Reportable Segments
Reportable Segments
Total sales and revenues	4,577	3,961	13,567	11,258
Depreciation and amortization	159	165	474	485
Consolidated profit before taxes	973	743	2,859	1,982
Segment assets	8,302		8,302		7,564
Capital expenditures	161	113	463	320
Energy & Transportation | Intersegment sales and revenues
Reportable Segments
Total sales and revenues	978	877	2,931	2,484
Financial Products Segment | Reportable Segments Including Intersegment Eliminations
Reportable Segments
Total sales and revenues	845	774	2,467	2,310
Financial Products Segment | Reportable Segments
Reportable Segments
Total sales and revenues	845	774	2,467	2,310
Depreciation and amortization	212	204	627	616
Consolidated profit before taxes	201	185	476	559
Segment assets	35,729		35,729		$ 34,893
Capital expenditures	298	308	1,192	1,018
Financial Products Segment | Intersegment sales and revenues
Reportable Segments
Total sales and revenues	$ 0	$ 0	$ 0	$ 0