Contractual term extensions (months) for modified finance receivables.

No definition available.

Name:	pcar_FinancingReceivableModificationsTermExtension
Namespace Prefix:	pcar_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual terms of retails loans and finance leases.

+ References

No definition available.

+ Details

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Namespace Prefix:	pcar_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

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

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable modified as troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
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+ Details

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

- Definition

Reflects the amount of the write-down related to a troubled debt restructuring.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
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+ Details

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

- Definition

Carrying amount as of the balance sheet date of assets other than real property that were received in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash inflow from the sale assets received in full or partial satisfaction of a receivable including real and personal property; equity interests in corporations, partnerships, and joint ventures; and beneficial interests in trusts. Foreclosed assets also include loans that are treated as if the underlying collateral had been foreclosed because the institution has taken possession of the collateral, even though legal foreclosure or repossession proceedings have not taken place.

+ References

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+ Details

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Balance Type:	debit
Period Type:	duration

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Namespace Prefix:
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- Details

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- Details

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Finance and Other Receivables - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable	$ 32.4		$ 29.5
Loans accounted for as troubled debt restructurings	46.7		14.1
TDRs charged-off during the period	0.1
Repossessed inventory	23.7		$ 25.6
Proceeds from the sales of repossessed assets	$ 47.5	$ 30.4
Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Months contractual terms extended	3 months		5 months
Financial Services \| Loans and Leases \| Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual terms of retails loans and finance leases	36 months
Financial Services \| Loans and Leases \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual terms of retails loans and finance leases	60 months
Financial Services \| Financing Receivable \| Maximum \| Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of portfolio assets	5.00%