Changes in Warranty and R&M Reserves (Detail) (USD $) In Millions	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Product Liability Contingency [Line Items]
Beginning balance	$ 372.2	$ 386.4
Cost accruals and revenue deferrals	137.5	84.5
Payments and revenue recognized	(101.3)	(99.2)
Currency translation	19.6	(37.2)
Ending balance	$ 428.0	$ 334.5

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard, extended warranty protection rights granted to customers, repair and maintenance contracts and related revenue deferrals.

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

- Definition

Total Increase or Decrease in the standard product warranties, extended product warranties, and repair and maintenance reserves due to currency translation.

+ Details

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

- Definition

Represents the aggregate decrease in the reserve related to payments to satisfy claims for standard product warranties, extended product warranties, repair and maintenance contracts and related revenue recognized.

+ Details

Name:	pcar_WarrantyAndRepairMaintenanceReservesDecrease
Namespace Prefix:	pcar
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the aggregate increase in the reserve for standard product warranties, extended product warranties, repair & maintenance contracts issued during the reporting period and related revenue deferrals.

+ Details

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Namespace Prefix:	pcar
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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.

+ Details

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