Changes in product Support Liabilities (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Product Liability Contingency [Line Items]
Beginning balance	$ 448.7	$ 372.2
Cost accruals and revenue deferrals	87.7	57.2
Payments and revenue recognized	(58.6)	(43.8)
Currency translation	8.2	14.1
Ending balance	$ 486.0	$ 399.7

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.

No definition available.

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