Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)
Accounting Policies [Abstract]
Number of portfolio segments | Segment	2
Receivables more than 90 days past due still accruing	$ 0	$ 0
Interest rate derivative portfolio	$ 1,200,000
Preferred stock dividend percentage	6.00%
Ownership percentage of PACCAR	100.00%
Internal Revenue Service (IRS)
Accounting Policies [Abstract]
Income tax examination, description	the United States Internal Revenue Service has completed examinations of PACCAR’s tax returns for all years through 2016. PACCAR’s tax returns remain subject to examination in other jurisdictions for the years ranging from 2012 through 2023.
Earliest Tax Year | Internal Revenue Service (IRS)
Accounting Policies [Abstract]
Tax years subject to examination	2012
Latest Tax Year | Internal Revenue Service (IRS)
Accounting Policies [Abstract]
Tax years subject to examination	2023
Maximum | Finance Leases Financing Receivable
Accounting Policies [Abstract]
Origination costs, amortization period	60 months
Maximum | Loans Receivable
Accounting Policies [Abstract]
Contractual term of regular payment of principal and interest	60 months
Minimum | Finance Leases Financing Receivable
Accounting Policies [Abstract]
Origination costs, amortization period	36 months
Minimum | Loans Receivable
Accounting Policies [Abstract]
Contractual term of regular payment of principal and interest	36 months
Accounting Standards Update 2022-02
Accounting Policies [Abstract]
Change in accounting principle, accounting standards update adoption date	Jan. 01, 2023
Description	Financial Instruments – Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures
Accounting Standards Update 2023-09
Accounting Policies [Abstract]
Description	Financial Accounting Standards Board (FASB) issued ASU 2023-09, Income Taxes (Topic 740)
Change in accounting principle, accounting standards update, immaterial effect	true
Extended Maturity
Accounting Policies [Abstract]
Modifications extended contractual terms	3 months	3 months