The percentage points added to the reference rate to compute the variable rate on the debt instrument.

Name:	cat_DebtInstrumentBasisSpreadOnVariableRate
Namespace Prefix:	cat
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ Details

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

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 59

+ Details

Name:	us-gaap_BusinessCombinationAcquisitionRelatedCosts
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Increase for additional borrowings on the debt instrument during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph f
-Article 4

+ Details

Name:	us-gaap_DebtInstrumentIncreaseAdditionalBorrowings
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Interest rate stated in the contractual debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap
Data Type:	us-types:percentItemType
Balance Type:	na
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Subsequent Events (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended	0 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	May 24, 2011 FLoating Rate Senior Notes Due in 2012 Member	May 24, 2011 FLoating Rate Senior Notes Due in 2013 Member	May 24, 2011 Senior Notes Due in 2014 at 1.375 Percent Member	May 24, 2011 Senior Notes Due in 2021 at 3.90 Percent Member	May 24, 2011 Senior Notes Due in 2041 at 5.20 Percent Member
Debt
Debt instrument, interest rate (as a percent)					1.375%	3.90%	5.20%
Additional borrowing			$ 500	$ 750	$ 750	$ 1,250	$ 1,250
Debt Instrument, Basis Spread on Variable Rate			Three-month USD LIBOR	Three-month USD LIBOR
Additional average spread over LIBOR (as a percent)			0.10%	0.17%
Cost related to acquisition	$ 204	$ 249