Cat Financial Financing Activities (Details 3) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Allowance for Credit Loss Activity
Balance at beginning of year	$ 366	$ 362
Receivables written off	(92)	(210)
Recoveries on receivables previously written off	36	52
Provision for credit losses	91	168
Other		(6)
Balance at end of period	401	366
Allowance for Credit Losses
Individually evaluated for impairment	75	56
Collectively evaluated for impairment	326	310
Ending Balance	401	366
Recorded Investment in Finance Receivables
Individually evaluated for impairment	730	575
Collectively evaluated for impairment	21,690	19,405
Ending balance-recorded investment in finance receivables	22,420	19,980
Customer
Allowance for Credit Loss Activity
Balance at beginning of year	360	357
Receivables written off	(92)	(210)
Recoveries on receivables previously written off	36	52
Provision for credit losses	90	167
Other		(6)
Balance at end of period	394	360
Allowance for Credit Losses
Individually evaluated for impairment	75	56
Collectively evaluated for impairment	319	304
Ending Balance	394	360
Recorded Investment in Finance Receivables
Individually evaluated for impairment	730	575
Collectively evaluated for impairment	18,311	17,018
Ending balance-recorded investment in finance receivables	19,041	17,593
Dealer
Allowance for Credit Loss Activity
Balance at beginning of year	6	5
Receivables written off	0	0
Recoveries on receivables previously written off	0	0
Provision for credit losses	1	1
Other		0
Balance at end of period	7	6
Allowance for Credit Losses
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	7	6
Ending Balance	7	6
Recorded Investment in Finance Receivables
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	3,379	2,387
Ending balance-recorded investment in finance receivables	$ 3,379	$ 2,387