Transactions with Related Parties (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction
Dividend paid to Caterpillar									$ 25	$ 400	$ 725
Maximum borrowing capacity from Caterpillar, Variable lending agreements	$ 2,610								2,610
Maximum lending capacity to Caterpillar, Variable lending agreements	2,050								2,050
Payable to Caterpillar - borrowings	618				$ 1,518				618	1,518	1,638
Payable to Caterpillar - other	75				83				75	83	85
Notes receivable from Caterpillar	296				662				296	662	559
Other receivables from Caterpillar	494				480				494	480
Discounts earned on purchased receivables									455	375	253
Recorded Investment in Finance Receivables	28,256				28,434				28,256	28,434
Total revenues	725	$ 748	$ 757	$ 736	699	$ 735	$ 723	$ 690	2,966	2,847	2,689
Depreciation on equipment leased to others									813	819	810
Caterpillar
Related Party Transaction
Dividend paid to Caterpillar									25	400	725
Maximum borrowing capacity from Caterpillar, Variable lending agreements	2,610								2,610
Maximum lending capacity to Caterpillar, Variable lending agreements	2,050								2,050
Amount available, Committed credit facility extended to Caterpillar	2,000								2,000
Other receivables from Caterpillar	64				33				64	33	31
Interest expense, Caterpillar									32	35	21
Interest income on Notes Receivable with Caterpillar									26	30	74
Fees on committed credit facility extended to Caterpillar									5	40	40
Purchases of receivables from Caterpillar									42,817	42,961	34,667
Discounts earned on purchased receivables									455	375	253
Marketing program payments received									351	335	277
Total portfolio, which includes Finance receivables, net and Equipment on operating lease, net	139				56				139	56
Total revenues									16	9	4
Depreciation on equipment leased to others									11	5	3
Amount of our portfolio that is subject to guarantees by Caterpillar	562				450				562	450
Charges for employee medical plans and postretirement benefit plans administered by Caterpillar									35	34	31
Contributions to defined benefit plans									9	9	8
Stock based compensation expense									8	8	8
Operational and administrative support charges reimbursed to Caterpillar									46	35	30
Administrative support services to certain Caterpillar subsidiaries reimbursed by Caterpillar									13	11	9
Caterpillar Purchased Receivables
Related Party Transaction
Recorded Investment in Finance Receivables	$ 4,448				$ 4,691				$ 4,448	$ 4,691	$ 3,461