Residual Value Obligation and Deferred Lease Revenue (Detail) - Truck, Parts and Other - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Property Subject to or Available for Operating Lease [Line Items]
Residual value guarantees	$ 541.7	$ 591.1
Deferred lease revenues	211.3	251.3
Residual value guarantees and deferred revenues, Total	$ 753.0	$ 842.4

Residual value obligation including both short-term and long-term obligation.

No definition available.

Name:	pcar_ResidualValueGuarantees
Namespace Prefix:	pcar_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Total amount of residual value guarantees and deferred lease revenues.

+ References

No definition available.

+ Details

Name:	pcar_ResidualValueGuaranteesAndDeferredRevenues
Namespace Prefix:	pcar_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents revenue received, but not recognized for financial reporting purposes. Such deferred revenue may consist of and include amounts paid in advance by lessees and is net of the accumulated amortization of such amounts that to date have been recognized in revenue.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.15)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_DeferredRevenueLeasesNet
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.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=pcar_TruckPartsAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: