Product Support Liabilities - Additional Information (Detail) $ in Millions	Dec. 31, 2024 USD ($)
Product Warranties Disclosures [Abstract]
Deferred revenues on extended warranties and R&M recognize, in 2025	$ 392.7
Deferred revenues on extended warranties and R&M recognize, in 2026	384.2
Deferred revenues on extended warranties and R&M recognize, in 2027	275.9
Deferred revenues on extended warranties and R&M recognize, in 2028	159.8
Deferred revenues on extended warranties and R&M recognize, in 2029	88.0
Deferred revenues on extended warranties and R&M recognize, thereafter	$ 1.6

Deferred revenue extended warranties and repair and maintenance recognize thereafter.

No definition available.

Name:	pcar_DeferredRevenueExtendedWarrantiesAndRepairAndMaintenanceRecognizeThereafter
Namespace Prefix:	pcar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Deferred revenue extended warranties and repair and maintenance recognize year five.

No definition available.

Name:	pcar_DeferredRevenueExtendedWarrantiesAndRepairAndMaintenanceRecognizeYearFive
Namespace Prefix:	pcar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Deferred revenue extended warranties and repair and maintenance recognize year four.

No definition available.

Name:	pcar_DeferredRevenueExtendedWarrantiesAndRepairAndMaintenanceRecognizeYearFour
Namespace Prefix:	pcar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Deferred revenue extended warranties and repair and maintenance recognize year one.

No definition available.

Name:	pcar_DeferredRevenueExtendedWarrantiesAndRepairAndMaintenanceRecognizeYearOne
Namespace Prefix:	pcar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Deferred revenue extended warranties and repair and maintenance recognize year three.

No definition available.

Name:	pcar_DeferredRevenueExtendedWarrantiesAndRepairAndMaintenanceRecognizeYearThree
Namespace Prefix:	pcar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Deferred revenue extended warranties and repair and maintenance recognize year two.

No definition available.

Name:	pcar_DeferredRevenueExtendedWarrantiesAndRepairAndMaintenanceRecognizeYearTwo
Namespace Prefix:	pcar_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

No definition available.

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