Transactions with Related Parties (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction
Dividend paid to Caterpillar									$ 600	$ 400	$ 200
Maximum borrowing capacity from Caterpillar, Variable lending agreements	$ 2,280								2,280
Maximum lending capacity to Caterpillar, Variable lending agreements	1,290								1,290
Amount available, Committed credit facility extended to Caterpillar	2,000								2,000
Notes payable to Caterpillar	1,096				$ 1,108				1,096	1,108	1,118
Notes receivable from Caterpillar	490				414				490	414	345
Discounts earned on purchased receivables									222	243	233
Total revenues	648	$ 653	$ 683	$ 689	703	$ 743	$ 728	$ 711	2,673	2,885	2,785
Depreciation on equipment leased to others									836	870	770
Caterpillar
Related Party Transaction
Dividend paid to Caterpillar									600	400	200
Maximum borrowing capacity from Caterpillar, Variable lending agreements	2,280								2,280
Maximum lending capacity to Caterpillar, Variable lending agreements	1,290								1,290
Amount available, Committed credit facility extended to Caterpillar	2,000								2,000
Interest expense, Caterpillar									6	7	7
Interest income on Notes Receivable with Caterpillar									21	18	19
Fees on committed credit facility extended to Caterpillar									40	41	41
Purchases of receivables from Caterpillar									33,154	36,816	33,018
Discounts earned on purchased receivables									222	243	233
Balance of purchased receivables	2,601				3,238				2,601	3,238	3,092
Marketing program payments received									188	173	189
Amount of our portfolio that is subject to guarantees by Caterpillar	418				568				418	568
Charges for employee medical plans and postretirement benefit plans administered by Caterpillar									29	30	27
Contributions to defined benefit plans									7	7	7
Stock based compensation expense									12	11	11
Operational and administrative support charges reimbursed to Caterpillar									37	37	33
Administrative support services to certain Caterpillar subsidiaries reimbursed by Caterpillar									12	12	12
Caterpillar Wholly-Owned Dealers
Related Party Transaction
Total portfolio, which includes finance receivables and equipment on operating lease, net of depreciation	$ 49				$ 58				49	58
Total revenues									9	11	11
Depreciation on equipment leased to others									$ 7	$ 9	$ 9