Segment and Geographic Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information
External Revenues	$ 699	$ 735	$ 723	$ 690	$ 678	$ 673	$ 676	$ 662	$ 2,847	$ 2,689	$ 2,595
Profit before income taxes	46	$ 163	$ 100	$ 124	133	$ 126	$ 164	$ 167	433	590	561
Interest Expense									757	667	611
Depreciation on equipment leased to others									819	810	841
Provision for credit losses									354	132	135
Assets	34,181				33,160				34,181	33,160	33,615
Capital expenditures									1,559	1,373	1,636
Operating Segments
Segment Reporting Information
External Revenues									2,789	2,630	2,547
Profit before income taxes									504	664	620
Interest Expense									740	645	604
Depreciation on equipment leased to others									818	808	838
Provision for credit losses									347	137	138
Assets	32,598				31,888				32,598	31,888	32,383
Capital expenditures									1,454	1,365	1,627
Unallocated
Segment Reporting Information
External Revenues									92	90	80
Profit before income taxes									(267)	(220)	(138)
Interest Expense									248	193	116
Depreciation on equipment leased to others									1	0	0
Provision for credit losses									0	0	0
Assets	1,957				1,719				1,957	1,719	1,688
Capital expenditures									104	8	6
Timing
Segment Reporting Information
External Revenues									(34)	(31)	(32)
Profit before income taxes									(1)	(6)	(12)
Interest Expense									0	0	0
Depreciation on equipment leased to others									0	2	3
Provision for credit losses									7	(5)	(3)
Assets	55				53				55	53	27
Capital expenditures									1	0	3
Methodology
Segment Reporting Information
External Revenues									0	0	0
Profit before income taxes									197	152	91
Interest Expense									(231)	(171)	(109)
Depreciation on equipment leased to others									0	0	0
Provision for credit losses									0	0	0
Assets	(159)				(256)				(159)	(256)	(220)
Capital expenditures									0	0	0
Inter-segment Eliminations
Segment Reporting Information
External Revenues									0	0	0
Profit before income taxes									0	0	0
Interest Expense									0	0	0
Depreciation on equipment leased to others									0	0	0
Provision for credit losses									0	0	0
Assets	(270)				(244)				(270)	(244)	(263)
Capital expenditures									0	0	0
North America | Operating Segments
Segment Reporting Information
External Revenues									1,533	1,337	1,230
Profit before income taxes									434	353	326
Interest Expense									363	306	287
Depreciation on equipment leased to others									572	520	477
Provision for credit losses									42	36	28
Assets	15,632				14,790				15,632	14,790	14,925
Capital expenditures									1,108	992	1,174
Europe | Operating Segments
Segment Reporting Information
External Revenues									279	307	268
Profit before income taxes									14	116	86
Interest Expense									50	37	33
Depreciation on equipment leased to others									71	80	83
Provision for credit losses									58	4	0
Assets	4,862				4,332				4,862	4,332	3,834
Capital expenditures									108	103	147
Asia/Pacific | Operating Segments
Segment Reporting Information
External Revenues									357	267	254
Profit before income taxes									168	99	82
Interest Expense									111	87	81
Depreciation on equipment leased to others									18	25	29
Provision for credit losses									(5)	(5)	3
Assets	4,639				4,214				4,639	4,214	3,620
Capital expenditures									14	6	74
Latin America | Operating Segments
Segment Reporting Information
External Revenues									254	292	320
Profit before income taxes									(3)	5	11
Interest Expense									101	121	118
Depreciation on equipment leased to others									27	38	57
Provision for credit losses									73	55	69
Assets	2,972				3,407				2,972	3,407	3,861
Capital expenditures									32	54	26
Caterpillar Power Finance | Operating Segments
Segment Reporting Information
External Revenues									110	155	167
Profit before income taxes									(143)	42	66
Interest Expense									55	44	38
Depreciation on equipment leased to others									2	3	4
Provision for credit losses									171	39	31
Assets	2,259				2,746				2,259	2,746	3,409
Capital expenditures									0	0	0
Mining | Operating Segments
Segment Reporting Information
External Revenues									256	272	308
Profit before income taxes									34	49	49
Interest Expense									60	50	47
Depreciation on equipment leased to others									128	142	188
Provision for credit losses									8	8	7
Assets	$ 2,234				$ 2,399				2,234	2,399	2,734
Capital expenditures									$ 192	$ 210	$ 206