Represents the number of shares of the entity's treasury stock given as a matching contribution to the defined contribution plans.

Name:	cat_EmployerMatchingContributionToDefinedContributionPlansSharesOfStock
Namespace Prefix:	cat
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the value of the entity's treasury stock given as a contribution to the defined contribution plans.

+ Details

Name:	cat_EmployerMatchingContributionToDefinedContributionPlansValueOfStock
Namespace Prefix:	cat
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents high end of range of the percentage of compensation contributed by employer to defined contribution plan as an annual employer non-elective contribution.

+ Details

Name:	cat_PercentageOfCompensationContributedAnnuallyByEmployerHighEndOfRange
Namespace Prefix:	cat
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents low end of range of the percentage of compensation contributed by employer to defined contribution plan as an annual employer non-elective contribution.

+ Details

Name:	cat_PercentageOfCompensationContributedAnnuallyByEmployerLowEndOfRange
Namespace Prefix:	cat
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the percentage of compensation contributed by the U.S. employees to defined contribution plans that are generally eligible for employer matching contributions.

+ Details

Name:	cat_PercentageOfCompensationContributedToDefinedContributionPlansByEmployees
Namespace Prefix:	cat
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the percentage of compensation contributed by the U.S. employees accruing benefits under defined benefit pension plan to defined contribution plans that are generally eligible for employer matching contributions for employees.

+ Details

Name:	cat_PercentageOfCompensationContributedToDefinedContributionPlansByEmployeesAccruingBenefitUnderDefinedBenefitPensionPlan
Namespace Prefix:	cat
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the percentage that the employer generally matches on employee contributions to U.S. defined contribution plans.

+ Details

Name:	cat_PercentageOfEmployeesContributionContributedByEmployer
Namespace Prefix:	cat
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the percentage that the employer generally matches of employee contributions to U.S. defined contribution plans for employees accruing benefits under a defined benefit pension plan.

+ Details

Name:	cat_PercentageOfEmployeesContributionContributedByEmployerAccruingBenefitUnderDefinedBenefitPensionPlan
Namespace Prefix:	cat
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

+ Details

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

Postretirement Benefits (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Jan. 02, 2011
Defined contribution plans
Costs related to defined contribution plans (in dollars)	$ 17	$ 85	$ 175	$ 184
U.S. Plans
Defined contribution plans
Employer matching contribution to defined contribution plans, value of stock (in dollars)		31		93
Employer matching contribution to defined contribution plans, shares of stock (in shares)		0.5		1.5
Percentage that the employer generally matches of employee contributions to U.S. defined contribution plans (as a percent)					100.00%
Employee compensation percentage contributed to defined contribution plan eligible for employer matching contributions (as a percent)					6.00%
Percentage that the employer generally matches of employee contributions to U.S. defined contribution plans for employees accruing benefits under a defined benefit pension plan (as a percent)					50.00%
Compensation percentage contributed to defined contribution plan eligible for employer matching contributions, for employees accruing benefits under defined benefit pension plan (as a percent)					6.00%
New annual employer contribution, percentage of compensation, low end of range (as a percent)					3.00%
New annual employer contribution, percentage of compensation, high end of range (as a percent)					5.00%
Costs related to defined contribution plans (in dollars)	3	77	135	160
Non-U.S. Plans
Defined contribution plans
Costs related to defined contribution plans (in dollars)	$ 14	$ 8	$ 40	$ 24