Cat Financial Financing Activities (Details 2) - Finance Receivables - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	$ 1,025	$ 805
Current	21,437	21,827
Ending balance-recorded investment in finance receivables	22,462	22,632
91+ Still Accruing	26	36
31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	279	165
61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	100	192
91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	646	448
Customer
Aging related to loans and finance leases
Ending balance-recorded investment in finance receivables	18,995	19,168
Customer | North America
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	137	128
Current	7,834	7,950
Ending balance-recorded investment in finance receivables	7,971	8,078
91+ Still Accruing	7	8
Customer | North America | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	74	71
Customer | North America | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	17	15
Customer | North America | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	46	42
Customer | Europe
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	150	77
Current	2,848	2,718
Ending balance-recorded investment in finance receivables	2,998	2,795
91+ Still Accruing	6	13
Customer | Europe | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	19	21
Customer | Europe | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	9	10
Customer | Europe | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	122	46
Customer | Asia Pacific
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	52	34
Current	2,399	2,009
Ending balance-recorded investment in finance receivables	2,451	2,043
91+ Still Accruing	5	5
Customer | Asia Pacific | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	30	13
Customer | Asia Pacific | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	14	7
Customer | Asia Pacific | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	8	14
Customer | Mining
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	14	64
Current	1,623	1,751
Ending balance-recorded investment in finance receivables	1,637	1,815
91+ Still Accruing	0	9
Customer | Mining | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	5	3
Customer | Mining | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	1
Customer | Mining | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	9	60
Customer | Latin America
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	134	234
Current	1,380	1,531
Ending balance-recorded investment in finance receivables	1,514	1,765
91+ Still Accruing	0	0
Customer | Latin America | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	35	37
Customer | Latin America | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	15	55
Customer | Latin America | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	84	142
Customer | Caterpillar Power Finance
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	459	196
Current	1,965	2,476
Ending balance-recorded investment in finance receivables	2,424	2,672
91+ Still Accruing	8	1
Customer | Caterpillar Power Finance | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	116	20
Customer | Caterpillar Power Finance | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	45	32
Customer | Caterpillar Power Finance | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	298	144
Dealer
Aging related to loans and finance leases
Ending balance-recorded investment in finance receivables	3,467	3,464
Dealer | North America
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Current	1,978	1,920
Ending balance-recorded investment in finance receivables	1,978	1,920
91+ Still Accruing	0	0
Dealer | North America | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | North America | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | North America | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Europe
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Current	321	222
Ending balance-recorded investment in finance receivables	321	222
91+ Still Accruing	0	0
Dealer | Europe | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Europe | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Europe | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Asia Pacific
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Current	473	553
Ending balance-recorded investment in finance receivables	473	553
91+ Still Accruing	0	0
Dealer | Asia Pacific | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Asia Pacific | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Asia Pacific | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Mining
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Current	4	4
Ending balance-recorded investment in finance receivables	4	4
91+ Still Accruing	0	0
Dealer | Mining | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Mining | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Mining | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Latin America
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	79	72
Current	610	691
Ending balance-recorded investment in finance receivables	689	763
91+ Still Accruing	0	0
Dealer | Latin America | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Latin America | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	72
Dealer | Latin America | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	79	0
Dealer | Caterpillar Power Finance
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Current	2	2
Ending balance-recorded investment in finance receivables	2	2
91+ Still Accruing	0	0
Dealer | Caterpillar Power Finance | 31 to 60 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Caterpillar Power Finance | 61 to 90 Days Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	0	0
Dealer | Caterpillar Power Finance | 91 Days of More Past Due
Aging related to loans and finance leases
Financing Receivable, Recorded Investment, Past Due	$ 0	$ 0