Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	Dec. 06, 2022	Dec. 31, 2024 USD ($) Segment shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($)	Jan. 17, 2023 shares
Accounting Policies [Abstract]
Reportable segments | Segment		3
Payment to acquire commitment value		$ 572,000,000
Equity method investment Contribution		207,600,000
Equity Method Investments		196,900,000
Depreciation and other expenses		$ 718,500,000	$ 590,700,000	$ 560,800,000
Liquid investments maturity period		90 days
Goodwill		$ 100,700,000	107,400,000
Derivative assets		$ 207,000,000	$ 21,000,000
Common stock dividend payable	50.00%
Common stock, issued | shares		524,400,000	523,300,000		174,035,361
Fractional shares paid in cash | shares					411
Restatement effect on percentage dividend	50.00%
ASU 2022-03
Accounting Policies [Abstract]
Change in accounting principle, accounting standards update, adopted [true false]		true
Change in accounting principle, accounting standards update adoption date		Jan. 01, 2024
Change in accounting principle, accounting standards update, immaterial effect [true false]		true
ASU 2023-07
Accounting Policies [Abstract]
Change in accounting principle, accounting standards update, adopted [true false]		true
Change in accounting principle, accounting standards update adoption date		Jan. 01, 2024
Change in accounting principle, accounting standards update, immaterial effect [true false]		true
O2023A Dividends
Accounting Policies [Abstract]
Dividends payable, date declared	Dec. 06, 2022
Dividends payable, date paid	Feb. 07, 2023
PACCAR
Accounting Policies [Abstract]
Equity method investment, ownership percentage		30.00%
Trade Receivables
Accounting Policies [Abstract]
Trade and other receivables, net		$ 1,538,000,000	$ 1,822,700,000
Other Receivables
Accounting Policies [Abstract]
Trade and other receivables, net		395,800,000	375,400,000
Financial Services
Accounting Policies [Abstract]
Total operating lease revenue		660,700,000	736,900,000	788,800,000
Financing receivable, recorded investment, 90 days past due and still accruing		$ 0	$ 0
Months contractual terms extended		4 months	3 months
Financial Services | Operating Lease
Accounting Policies [Abstract]
Total operating lease revenue		$ 660,700,000	$ 736,900,000	$ 788,800,000
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]		Net sales and revenues	Net sales and revenues	Net sales and revenues
Depreciation and other expenses		$ 602,200,000	$ 551,900,000	$ 490,000,000
Truck, Parts and Other
Accounting Policies [Abstract]
Standard product warranty, description		The Company generally offers one year warranties covering most of its vehicles and related aftermarket parts. For vehicles equipped with engines manufactured by PACCAR, the Company generally offers two year warranties on the engine.
Standard product warranty, term		1 year
Extended product warranty, description		Optional extended warranty and R&M contracts can be purchased for periods which generally range up to five years.
Trade and other receivables, net		$ 1,933,800,000	$ 2,198,100,000
Trade receivable days outstanding considered past due		30 days	30 days	30 days
Allowance for credit losses for Truck, Parts and Other		$ 1,200,000	$ 900,000
Net charge-offs		$ 0	0	$ 200,000
Engines manufactured by PACCAR | Truck, Parts and Other
Accounting Policies [Abstract]
Standard product warranty, term		2 years
Trucks | Truck Sales
Accounting Policies [Abstract]
Total operating lease revenue		$ 32,600,000	$ 69,700,000	$ 105,900,000
Maximum
Accounting Policies [Abstract]
Warranty period		5 years
Lease and guarantee periods (in years)		5 years
Equity method investment Contribution		$ 830,000,000
Estimated useful lives of equipment		10 years
Maximum | Financial Services
Accounting Policies [Abstract]
Operating lease term		5 years
Maximum | Financial Services | Loans and Leases
Accounting Policies [Abstract]
Contractual terms of retails loans and finance leases		5 years
Maximum | Truck, Parts and Other
Accounting Policies [Abstract]
Extended product warranty, term		5 years
Maximum | Trucks | Financial Services
Accounting Policies [Abstract]
Finance leases, lease term		5 years
Minimum
Accounting Policies [Abstract]
Lease and guarantee periods (in years)		3 years
Estimated useful lives of equipment		3 years
Minimum | Financial Services
Accounting Policies [Abstract]
Operating lease term		3 years
Minimum | Financial Services | Loans and Leases
Accounting Policies [Abstract]
Contractual terms of retails loans and finance leases		3 years
Minimum | Trucks | Financial Services
Accounting Policies [Abstract]
Finance leases, lease term		3 years