Cat Financial Financing Activities (Details 5 Non-accrual) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Period after which Collection of Future Income is Considered as Not Probable	120 days
Dealer
Financing Receivable, Nonaccrual [Line Items]
Interest income recognized for finance receivables on non-accrual status	$ 0
Recorded investment, non-accrual finance receivables		$ 78
Customer
Financing Receivable, Nonaccrual [Line Items]
Interest income recognized for finance receivables on non-accrual status	1
Finance Receivables \| Dealer
Financing Receivable, Nonaccrual [Line Items]
91 Still Accruing	0
Finance Receivables \| Customer
Financing Receivable, Nonaccrual [Line Items]
Non-accrual With an Allowance	703
Non-accrual Without an Allowance	1
91 Still Accruing	53	29
Recorded investment, non-accrual finance receivables	727
Finance Receivables \| North America \| Customer
Financing Receivable, Nonaccrual [Line Items]
Non-accrual With an Allowance	50
Non-accrual Without an Allowance	0
91 Still Accruing	20	15
Recorded investment, non-accrual finance receivables	44
Finance Receivables \| EAME \| Customer
Financing Receivable, Nonaccrual [Line Items]
Non-accrual With an Allowance	168
Non-accrual Without an Allowance	1
91 Still Accruing	5	4
Recorded investment, non-accrual finance receivables	165
Finance Receivables \| Asia Pacific \| Customer
Financing Receivable, Nonaccrual [Line Items]
Non-accrual With an Allowance	29
Non-accrual Without an Allowance	0
91 Still Accruing	12	8
Recorded investment, non-accrual finance receivables	21
Finance Receivables \| Mining \| Customer
Financing Receivable, Nonaccrual [Line Items]
Non-accrual With an Allowance	40
Non-accrual Without an Allowance	0
91 Still Accruing	9	0
Recorded investment, non-accrual finance receivables	47
Finance Receivables \| Latin America \| Dealer
Financing Receivable, Nonaccrual [Line Items]
Non-accrual With an Allowance	78
Finance Receivables \| Latin America \| Customer
Financing Receivable, Nonaccrual [Line Items]
Non-accrual With an Allowance	87
Non-accrual Without an Allowance	0
91 Still Accruing	0	2
Recorded investment, non-accrual finance receivables	89
Finance Receivables \| Caterpillar Power Finance \| Customer
Financing Receivable, Nonaccrual [Line Items]
Non-accrual With an Allowance	329
Non-accrual Without an Allowance	0
91 Still Accruing	7	$ 0
Recorded investment, non-accrual finance receivables	$ 361

Financing Receivables that are 91 days or more past due and still accruing.

No definition available.

Name:	cat_FinancingReceivable91dayspastdueandstillaccruing
Namespace Prefix:	cat_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the period after which collection of future income is considered as not probable.

+ References

No definition available.

+ Details

Name:	cat_PeriodAfterWhichCollectionOfFutureIncomeIsConsideredAsNotProbable
Namespace Prefix:	cat_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of interest income on financing receivable on nonaccrual status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of financing receivable on nonaccrual status with no allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableNonaccrualStatusLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable on nonaccrual status.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5111-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919258-210447

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reflects the carrying amount of loans deemed to be questionable as to collection on which no interest is continuing to be recognized.

+ References

+ Details

Name:	us-gaap_LoansAndLeasesReceivableImpairedNonperformingNonaccrualOfInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=cat_CustomerMember
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- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=cat_FinanceReceivableMember
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=srt_NorthAmericaMember
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_EMEAMember
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=srt_AsiaPacificMember
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Data Type:	na
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cat_MiningMember
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=srt_LatinAmericaMember
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cat_CaterpillarPowerFinanceMember
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