Cat Financial Financing Activities (Details 4) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 D	Dec. 31, 2011
Cat Financial Financing Activities
Period after which finance receivables are considered non-performing (in days)	120
Finance Receivables
Ending Balance - recorded investment in finance receivables	$ 21,726	$ 19,980
Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	21,078	19,508
Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	648	472
North America
Finance Receivables
Ending Balance - recorded investment in finance receivables	7,570	7,291
North America | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	7,478	7,179
North America | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	92	112
Europe
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,388	2,281
Europe | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,340	2,223
Europe | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	48	58
Asia Pacific
Finance Receivables
Ending Balance - recorded investment in finance receivables	3,615	3,038
Asia Pacific | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	3,585	3,014
Asia Pacific | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	30	24
Mining
Finance Receivables
Ending Balance - recorded investment in finance receivables	1,725	1,485
Mining | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	1,713	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	3,260	2,965
Latin America | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	3,091	2,857
Latin America | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	169	108
Caterpillar Power Finance
Finance Receivables
Ending Balance - recorded investment in finance receivables	3,168	2,920
Caterpillar Power Finance | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,871	2,762
Caterpillar Power Finance | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	297	158
Customer
Finance Receivables
Ending Balance - recorded investment in finance receivables	18,448	17,593
Customer | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	17,800	17,121
Customer | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	648	472
Customer | North America
Finance Receivables
Ending Balance - recorded investment in finance receivables	5,663	5,602
Customer | North America | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	5,571	5,490
Customer | North America | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	92	112
Customer | Europe
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,319	2,224
Customer | Europe | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,271	2,166
Customer | Europe | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	48	58
Customer | Asia Pacific
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,995	2,877
Customer | Asia Pacific | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,965	2,853
Customer | Asia Pacific | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	30	24
Customer | Mining
Finance Receivables
Ending Balance - recorded investment in finance receivables	1,724	1,485
Customer | Mining | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	1,712	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	2,579	2,485
Customer | Latin America | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,410	2,377
Customer | Latin America | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	169	108
Customer | Caterpillar Power Finance
Finance Receivables
Ending Balance - recorded investment in finance receivables	3,168	2,920
Customer | Caterpillar Power Finance | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	2,871	2,762
Customer | Caterpillar Power Finance | Nonperforming
Finance Receivables
Ending Balance - recorded investment in finance receivables	297	158
Dealer
Finance Receivables
Ending Balance - recorded investment in finance receivables	3,278	2,387
Dealer | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	3,278	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	1,907	1,689
Dealer | North America | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	1,907	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	69	57
Dealer | Europe | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	69	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	620	161
Dealer | Asia Pacific | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	620	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	681	480
Dealer | Latin America | Performing
Finance Receivables
Ending Balance - recorded investment in finance receivables	681	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