Cat Financial Financing Activities (Details 3) - Finance Receivables - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Allowance for credit loss activity:
Balance at beginning of year	$ 341	$ 336
Receivables written off	(157)	(158)
Recoveries on receivables previously written off	43	35
Provision for credit losses	128	133
Other	7	(5)
Balance at end of year	362	341
Allowance for Credit Losses:
Individually evaluated for impairment			$ 149	$ 85
Collectively evaluated for impairment			213	256
Ending Balance	341	336	362	341
Recorded Investment in Finance Receivables:
Individually evaluated for impairment			942	786
Collectively evaluated for impairment			21,690	21,611
Ending balance-recorded investment in finance receivables			22,632	22,397
Customer
Allowance for credit loss activity:
Balance at beginning of year	331	327
Receivables written off	(157)	(158)
Recoveries on receivables previously written off	43	35
Provision for credit losses	129	132
Other	7	5
Balance at end of year	353	331
Allowance for Credit Losses:
Individually evaluated for impairment			149	85
Collectively evaluated for impairment			204	246
Ending Balance	331	327	353	331
Recorded Investment in Finance Receivables:
Individually evaluated for impairment			942	786
Collectively evaluated for impairment			18,226	18,236
Ending balance-recorded investment in finance receivables			19,168	19,022
Dealer
Allowance for credit loss activity:
Balance at beginning of year	10	9
Receivables written off	0	0
Recoveries on receivables previously written off	0	0
Provision for credit losses	(1)	1
Other	0	0
Balance at end of year	9	10
Allowance for Credit Losses:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			9	10
Ending Balance	$ 10	$ 9	9	10
Recorded Investment in Finance Receivables:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			3,464	3,375
Ending balance-recorded investment in finance receivables			$ 3,464	$ 3,375