Financing Activities (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses
Balance at beginning of year	$ 426	$ 369
Receivables written off	(22)	(149)
Recoveries on receivables previously written off	12	47
Provision for credit losses	16	160
Adjustment due to sale of receivables	(1)	(2)
Foreign currency translation adjustment	(2)	1
Balance at end of period	429	426
Allowance for Credit Losses
Individually evaluated for impairment	101	73
Collectively evaluated for impairment	328	353
Allowance, Ending Balance	429	426
Recorded Investment in Finance Receivables
Individually evaluated for impairment	736	682
Collectively evaluated for impairment	28,044	27,901
Recorded Investment in Finance Receivables, Ending Balance	28,780	28,583
Customer
Financing Receivable, Allowance for Credit Losses
Balance at beginning of year	414	360
Receivables written off	(22)	(149)
Recoveries on receivables previously written off	12	47
Provision for credit losses	15	157
Adjustment due to sale of receivables	(1)	(2)
Foreign currency translation adjustment	(2)	1
Balance at end of period	416	414
Allowance for Credit Losses
Individually evaluated for impairment	101	73
Collectively evaluated for impairment	315	341
Allowance, Ending Balance	416	414
Recorded Investment in Finance Receivables
Individually evaluated for impairment	736	682
Collectively evaluated for impairment	19,385	19,201
Recorded Investment in Finance Receivables, Ending Balance	20,121	19,883
Dealer
Financing Receivable, Allowance for Credit Losses
Balance at beginning of year	9	6
Receivables written off	0	0
Recoveries on receivables previously written off	0	0
Provision for credit losses	1	3
Adjustment due to sale of receivables	0	0
Foreign currency translation adjustment	0	0
Balance at end of period	10	9
Allowance for Credit Losses
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	10	9
Allowance, Ending Balance	10	9
Recorded Investment in Finance Receivables
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	5,493	5,586
Recorded Investment in Finance Receivables, Ending Balance	5,493	5,586
Caterpillar Purchased Receivables
Financing Receivable, Allowance for Credit Losses
Balance at beginning of year	3	3
Receivables written off	0	0
Recoveries on receivables previously written off	0	0
Provision for credit losses	0	0
Adjustment due to sale of receivables	0	0
Foreign currency translation adjustment	0	0
Balance at end of period	3	3
Allowance for Credit Losses
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	3	3
Allowance, Ending Balance	3	3
Recorded Investment in Finance Receivables
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	3,166	3,114
Recorded Investment in Finance Receivables, Ending Balance	$ 3,166	$ 3,114