Cat Financial Financing Activities (Details 4) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Receivables [Abstract]
Period after which finance receivables are considered non-performing (in days)	120 days
Finance Receivables
Ending balance-recorded investment in finance receivables	$ 22,420	$ 19,980
Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	21,811	19,508
Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	609	472
North America
Finance Receivables
Ending balance-recorded investment in finance receivables	7,755	7,291
North America | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	7,678	7,179
North America | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	77	112
Europe
Finance Receivables
Ending balance-recorded investment in finance receivables	2,533	2,281
Europe | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	2,489	2,223
Europe | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	44	58
Asia Pacific
Finance Receivables
Ending balance-recorded investment in finance receivables	3,745	3,038
Asia Pacific | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	3,705	3,014
Asia Pacific | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	40	24
Mining
Finance Receivables
Ending balance-recorded investment in finance receivables	1,840	1,485
Mining | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	1,828	1,473
Mining | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	12	12
Latin America
Finance Receivables
Ending balance-recorded investment in finance receivables	3,384	2,965
Latin America | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	3,234	2,857
Latin America | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	150	108
Caterpillar Power Finance
Finance Receivables
Ending balance-recorded investment in finance receivables	3,163	2,920
Caterpillar Power Finance | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	2,877	2,762
Caterpillar Power Finance | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	286	158
Customer
Finance Receivables
Ending balance-recorded investment in finance receivables	19,041	17,593
Customer | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	18,432	17,121
Customer | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	609	472
Customer | North America
Finance Receivables
Ending balance-recorded investment in finance receivables	5,785	5,602
Customer | North America | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	5,708	5,490
Customer | North America | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	77	112
Customer | Europe
Finance Receivables
Ending balance-recorded investment in finance receivables	2,455	2,224
Customer | Europe | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	2,411	2,166
Customer | Europe | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	44	58
Customer | Asia Pacific
Finance Receivables
Ending balance-recorded investment in finance receivables	3,103	2,877
Customer | Asia Pacific | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	3,063	2,853
Customer | Asia Pacific | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	40	24
Customer | Mining
Finance Receivables
Ending balance-recorded investment in finance receivables	1,839	1,485
Customer | Mining | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	1,827	1,473
Customer | Mining | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	12	12
Customer | Latin America
Finance Receivables
Ending balance-recorded investment in finance receivables	2,696	2,485
Customer | Latin America | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	2,546	2,377
Customer | Latin America | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	150	108
Customer | Caterpillar Power Finance
Finance Receivables
Ending balance-recorded investment in finance receivables	3,163	2,920
Customer | Caterpillar Power Finance | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	2,877	2,762
Customer | Caterpillar Power Finance | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	286	158
Dealer
Finance Receivables
Ending balance-recorded investment in finance receivables	3,379	2,387
Dealer | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	3,379	2,387
Dealer | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables	0	0
Dealer | North America
Finance Receivables
Ending balance-recorded investment in finance receivables	1,970	1,689
Dealer | North America | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	1,970	1,689
Dealer | North America | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables
Dealer | Europe
Finance Receivables
Ending balance-recorded investment in finance receivables	78	57
Dealer | Europe | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	78	57
Dealer | Europe | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables
Dealer | Asia Pacific
Finance Receivables
Ending balance-recorded investment in finance receivables	642	161
Dealer | Asia Pacific | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	642	161
Dealer | Asia Pacific | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables
Dealer | Mining
Finance Receivables
Ending balance-recorded investment in finance receivables	1	0
Dealer | Mining | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	1	0
Dealer | Mining | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables
Dealer | Latin America
Finance Receivables
Ending balance-recorded investment in finance receivables	688	480
Dealer | Latin America | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	688	480
Dealer | Latin America | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables
Dealer | Caterpillar Power Finance
Finance Receivables
Ending balance-recorded investment in finance receivables	0	0
Dealer | Caterpillar Power Finance | Performing
Finance Receivables
Ending balance-recorded investment in finance receivables	0	0
Dealer | Caterpillar Power Finance | Nonperforming
Finance Receivables
Ending balance-recorded investment in finance receivables