Reconciliations of consolidated profit before taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	$ 1,775	$ 863	$ 5,642	$ 3,054
Operating Segments | Reportable Segments
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	2,025	1,386	6,657	4,479
Operating Segments | Reportable Segments | Construction Industries
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	859	585	2,918	1,743
Operating Segments | Reportable Segments | Resource Industries
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	297	167	986	623
Operating Segments | Reportable Segments | Energy & Transportation
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	696	492	2,093	1,718
Operating Segments | Reportable Segments | Financial Products Segment
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	173	142	660	395
Operating Segments | All Other operating segments
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	5	27	(2)	31
Intersegment Eliminations | Cost Centers
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	19	9	51	18
Intersegment Eliminations | Corporate Costs
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(189)	(122)	(576)	(409)
Intersegment Eliminations | Timing
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(40)	(39)	(230)	(90)
Intersegment Eliminations | Restructuring Costs
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(35)	(87)	(124)	(211)
Intersegment Eliminations | Inventory/cost of sales
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	73	(7)	80	(25)
Intersegment Eliminations | Postretirement Benefits Expense
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	116	(32)	270	253
Intersegment Eliminations | Stock-Based Compensation Expense
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(58)	(55)	(169)	(169)
Intersegment Eliminations | Financing Costs
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(103)	(125)	(342)	(324)
Intersegment Eliminations | Currency
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	19	(22)	255	(230)
Intersegment Eliminations | Other Income Expense Methodology Differences
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	(80)	(72)	(201)	(244)
Intersegment Eliminations | Other
Reconciliation of Consolidated profit (loss) before taxes
Reclassifications before tax	$ 23	$ 2	$ (27)	$ (25)