Borrowings and Credit Arrangements - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Apr. 30, 2011 MXN	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 MXN	Dec. 31, 2015 USD ($)	Dec. 31, 2015 EUR (€)
Debt Disclosure [Line Items]
Interest paid on borrowings		$ 101,300,000	$ 136,300,000	$ 149,300,000
Line of credit, maximum capacity						$ 3,435,000,000
Line of credit, unused borrowing capacity						3,256,400,000
Syndicated loan facility
Debt Disclosure [Line Items]
Line of credit, maximum capacity						3,000,000,000
PACCAR's U.S. finance subsidiary | Medium-term Notes
Debt Disclosure [Line Items]
Debt outstanding						4,400,000,000
Registration expiration		2018-11
PACCAR's European finance subsidiary | Medium-term Notes
Debt Disclosure [Line Items]
Debt, unused borrowing capacity | €							€ 269,000,000
Debt, borrowing capacity | €							€ 1,500,000,000
Debt, renewal period		Annually through the filing of new listing particulars
PACCAR's Mexico finance subsidiary | Commercial Papers
Debt Disclosure [Line Items]
Maximum limit of borrowing capacity | MXN	MXN 5,000,000,000
PACCAR's Mexico finance subsidiary | Medium-term Notes
Debt Disclosure [Line Items]
Registration expiration		2016-04
Debt, unused borrowing capacity | MXN					MXN 8,035,000,000
PACCAR's Mexico finance subsidiary | Medium-term Notes | Commercial Papers
Debt Disclosure [Line Items]
Debt, borrowing capacity | MXN	MXN 10,000,000,000
Financial Services
Debt Disclosure [Line Items]
Commercial paper and term notes			8,094,700,000			8,415,400,000
Fair value hedges and unamortized discounts, net		$ (1,100,000)	(1,000,000)
Truck, Parts and Other
Debt Disclosure [Line Items]
Capitalized interest			$ 1,300,000	$ 10,300,000
Maximum | PACCAR's Mexico finance subsidiary | Commercial Papers
Debt Disclosure [Line Items]
Commercial paper expiration period	1 year
Expires in June 2016 | Syndicated loan facility
Debt Disclosure [Line Items]
Line of credit, maximum capacity						1,000,000,000
Line of credit, expiry date		2016-06
Expires in June 2019 | Syndicated loan facility
Debt Disclosure [Line Items]
Line of credit, maximum capacity						1,000,000,000
Line of credit, expiry date		2019-06
Expires in June 2020 | Syndicated loan facility
Debt Disclosure [Line Items]
Line of credit, maximum capacity						$ 1,000,000,000
Line of credit, expiry date		2020-06