Cat Financial Financing Activities (Details 4) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due
Period after which Collection of Future Income is Considered as Not Probable	120 days
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest		$ 0
Dealer
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest		0
Dealer | Latin America
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	$ 79
Finance Receivables | Customer
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	751	683
Finance Receivables | Customer | North America
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	44	38
Finance Receivables | Customer | Europe
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	124	37
Finance Receivables | Customer | Asia Pacific
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	4	10
Finance Receivables | Customer | Mining
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	10	63
Finance Receivables | Customer | Latin America
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	118	192
Finance Receivables | Customer | Caterpillar Power Finance
Financing Receivable, Recorded Investment, Past Due
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	$ 451	$ 343