Guarantees and Product Warranty (Details) (USD $) In Millions	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Guarantees and product warranty
Related liability	$ 10	$ 17	$ 14
Guarantor Obligations
Guarantees, maximum potential amount of future payments	420	623	579
Financial Special-Purpose Company's assets in Consolidated Statement of Financial Position	365	231	477
Financial Special-Purpose Company's liabilities in Consolidated Statement of Financial Position	365	231	477
Unused commitments and lines of credit for dealers	6,408	7,312	8,918
Unused commitments and lines of credit for customers	2,613	2,089	3,085
Caterpillar dealer guarantees
Guarantor Obligations
Guarantees, maximum potential amount of future payments	185	313	375
Customer guarantees
Guarantor Obligations
Guarantees, maximum potential amount of future payments	170	226	136
Limited indemnity
Guarantor Obligations
Guarantees, maximum potential amount of future payments	17	20	25
Other guarantees
Guarantor Obligations
Guarantees, maximum potential amount of future payments	$ 48	$ 64	$ 43

The carrying amount of the consolidated Financial Special-Purpose Company Variable Interest Entity's assets included in the reporting entity's statement of financial position.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The carrying amount of the consolidated Financial Special-Purpose Company Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

+ Details

Name:	cat_FinancialSpecialPurposeCompanyVariableInterestEntityConsolidatedCarryingAmountLiabilities
Namespace Prefix:	cat
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	cat_GuaranteesAndProductWarrantyDisclosureAbstract
Namespace Prefix:	cat
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the unused portion of commitments and lines of credit for customers.

+ Details

Name:	cat_UnusedCommitmentsAndLinesOfCreditForCustomers
Namespace Prefix:	cat
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the unused portion of commitments and lines of credit for dealers.

+ Details

Name:	cat_UnusedCommitmentsAndLinesOfCreditForDealers
Namespace Prefix:	cat
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph c

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph b

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant