Cat Financial Financing Activities (Details) - Finance Receivables - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2019	Dec. 31, 2018
Allowance for Credit Loss Activity
Balance at beginning of year	$ 507	$ 362
Receivables written off	(238)	(235)
Recoveries on receivables previously written off	31	46
Provision for credit losses	144	349
Other	(14)	(15)
Balance at end of period	430	507
Allowance for Credit Losses
Individually evaluated for impairment			$ 221	$ 302
Collectively evaluated for impairment			209	205
Ending Balance	430	362	430	507
Recorded Investment in Finance Receivables
Individually evaluated for impairment			743	936
Collectively evaluated for impairment			21,278	21,490
Ending balance-recorded investment in finance receivables			22,021	22,426
Customer
Allowance for Credit Loss Activity
Balance at beginning of year	486	353
Receivables written off	(238)	(235)
Recoveries on receivables previously written off	31	46
Provision for credit losses	120	337
Other	(14)	(15)
Balance at end of period	385	486
Allowance for Credit Losses
Individually evaluated for impairment			182	288
Collectively evaluated for impairment			203	198
Ending Balance	385	353	385	486
Recorded Investment in Finance Receivables
Individually evaluated for impairment			665	858
Collectively evaluated for impairment			17,622	18,152
Ending balance-recorded investment in finance receivables			18,287	19,010
Dealer
Allowance for Credit Loss Activity
Balance at beginning of year	21	9
Receivables written off	0	0
Recoveries on receivables previously written off	0	0
Provision for credit losses	24	12
Other	0	0
Balance at end of period	45	21
Allowance for Credit Losses
Individually evaluated for impairment			39	14
Collectively evaluated for impairment			6	7
Ending Balance	$ 45	$ 9	45	21
Recorded Investment in Finance Receivables
Individually evaluated for impairment			78	78
Collectively evaluated for impairment			3,656	3,338
Ending balance-recorded investment in finance receivables			$ 3,734	$ 3,416