Reconciliations of consolidated profit before taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	$ 1,870	$ 678	$ 3,867	$ 2,191
Operating Segments | Reportable Segments
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	2,359	1,442	4,632	3,093
Operating Segments | Reportable Segments | Construction Industries
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	1,024	518	2,059	1,158
Operating Segments | Reportable Segments | Resource Industries
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	361	152	689	456
Operating Segments | Reportable Segments | Energy & Transportation
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	731	624	1,397	1,226
Operating Segments | Reportable Segments | Financial Products Segment
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	243	148	487	253
Operating Segments | All Other operating segments
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(10)	(3)	(7)	4
Intersegment Eliminations | Cost Centers
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	11	(23)	32	9
Intersegment Eliminations | Corporate Costs
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(202)	(120)	(387)	(287)
Intersegment Eliminations | Timing
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(124)	(24)	(190)	(51)
Intersegment Eliminations | Restructuring Costs
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(25)	(96)	(89)	(124)
Intersegment Eliminations | Inventory/cost of sales
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	7	(38)	7	(18)
Intersegment Eliminations | Postretirement Benefits Expense
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	86	(118)	154	285
Intersegment Eliminations | Stock-Based Compensation Expense
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(69)	(67)	(111)	(114)
Intersegment Eliminations | Financing Costs
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(109)	(119)	(239)	(199)
Intersegment Eliminations | Currency
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	50	(60)	236	(208)
Intersegment Eliminations | Other Income Expense Methodology Differences
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(72)	(80)	(121)	(172)
Intersegment Eliminations | Other
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	$ (32)	$ (16)	$ (50)	$ (27)