Accounting Policies (Policies)	3 Months Ended
Accounting Policies (Policies)	Mar. 31, 2016
Accounting Policies [Abstract]
Investment in Marketable Debt Securities	The Company’s investments in marketable debt securities are classified as available-for-sale. These investments are stated at fair value with any unrealized gains or losses, net of tax, included as a component of accumulated other comprehensive income (loss) (AOCI). The Company utilizes third-party pricing services for all of its marketable debt security valuations. The Company reviews the pricing methodology used by the third-party pricing services, including the manner employed to collect market information. On a quarterly basis, the Company also performs review and validation procedures on the pricing information received from the third-party providers. These procedures help ensure that the fair value information used by the Company is determined in accordance with applicable accounting guidance. The Company evaluates its investment in marketable debt securities at the end of each reporting period to determine if a decline in fair value is other-than-temporary. Realized losses are recognized upon management’s determination that a decline in fair value is other-than-temporary. The determination of other-than-temporary impairment is a subjective process, requiring the use of judgments and assumptions regarding the amount and timing of recovery. The Company reviews and evaluates its investments at least quarterly to identify investments that have indications of other-than-temporary impairments. It is reasonably possible that a change in estimate could occur in the near term relating to other-than-temporary impairment. Accordingly, the Company considers several factors when evaluating debt securities for other-than-temporary impairment, including whether the decline in fair value of the security is due to increased default risk for the specific issuer or market interest-rate risk. In assessing default risk, the Company considers the collectability of principal and interest payments by monitoring changes to issuers’ credit ratings, specific credit events associated with individual issuers as well as the credit ratings of any financial guarantor, and the extent and duration to which amortized cost exceeds fair value. In assessing market interest rate risk, including benchmark interest rates and credit spreads, the Company considers its intent for selling the securities and whether it is more likely than not the Company will be able to hold these securities until the recovery of any unrealized losses.
Inventories	Inventories are stated at the lower of cost or market. Cost of inventories in the U.S. is determined principally by the last-in, first-out (LIFO) method. Cost of all other inventories is determined principally by the first-in, first-out (FIFO) method.
Allowance for Credit Losses	Allowance for Credit Losses The Company continuously monitors the payment performance of its finance receivables. For large retail finance customers and dealers with wholesale financing, the Company regularly reviews their financial statements and makes site visits and phone contact as appropriate. If the Company becomes aware of circumstances that could cause those customers or dealers to face financial difficulty, whether or not they are past due, the customers are placed on a watch list. The Company modifies loans and finance leases in the normal course of its Financial Services operations. The Company may modify loans and finance leases for commercial reasons or for credit reasons. Modifications for commercial reasons are changes to contract terms for customers that are not considered to be in financial difficulty. Insignificant delays are modifications extending terms up to three months for customers experiencing some short-term financial stress, but not considered to be in financial difficulty. Modifications for credit reasons are changes to contract terms for customers considered to be in financial difficulty. The Company’s modifications typically result in granting more time to pay the contractual amounts owed and charging a fee and interest for the term of the modification. When considering whether to modify customer accounts for credit reasons, the Company evaluates the creditworthiness of the customers and modifies those accounts that the Company considers likely to perform under the modified terms. When the Company modifies loans and finance leases for credit reasons and grants a concession, the modifications are classified as troubled debt restructurings (TDR). The Company does not typically grant credit modifications for customers that do not meet minimum underwriting standards since the Company normally repossesses the financed equipment in these circumstances. When such modifications do occur, they are considered TDRs. On average, modifications extended contractual terms by approximately three months in 2016 and seven months in 2015 and did not have a significant effect on the weighted average term or interest rate of the total portfolio at March 31, 2016 and December 31, 2015. The Company has developed a systematic methodology for determining the allowance for credit losses for its two portfolio segments, retail and wholesale. The retail segment consists of retail loans and direct and sales-type finance leases, net of unearned interest. The wholesale segment consists of truck inventory financing loans to dealers that are collateralized by trucks and other collateral. The wholesale segment generally has less risk than the retail segment. Wholesale receivables generally are shorter in duration than retail receivables, and the Company requires periodic reporting of the wholesale dealer’s financial condition, conducts periodic audits of the trucks being financed and in many cases, obtains guarantees or other security such as dealership assets. In determining the allowance for credit losses, retail loans and finance leases are evaluated together since they relate to a similar customer base, their contractual terms require regular payment of principal and interest, generally over 36 to 60 months, and they are secured by the same type of collateral. The allowance for credit losses consists of both specific and general reserves. The Company individually evaluates certain finance receivables for impairment. Finance receivables that are evaluated individually for impairment consist of all wholesale accounts and certain large retail accounts with past due balances or otherwise determined to be at a higher risk of loss. A finance receivable is impaired if it is considered probable the Company will be unable to collect all contractual interest and principal payments as scheduled. In addition, all retail loans and leases which have been classified as TDRs and all customer accounts over 90 days past due are considered impaired. Generally, impaired accounts are on non-accrual status. Impaired accounts classified as TDRs which have been performing for 90 consecutive days are placed on accrual status if it is deemed probable that the Company will collect all principal and interest payments. Impaired receivables are generally considered collateral dependent. Large balance retail and all wholesale impaired receivables are individually evaluated to determine the appropriate reserve for losses. The determination of reserves for large balance impaired receivables considers the fair value of the associated collateral. When the underlying collateral fair value exceeds the Company’s recorded investment, no reserve is recorded. Small balance impaired receivables with similar risk characteristics are evaluated as a separate pool to determine the appropriate reserve for losses using the historical loss information discussed below. The Company evaluates finance receivables that are not individually impaired on collective basis and determines the general allowance for credit losses for both retail and wholesale receivables based on historical loss information, using past due account data and current market conditions. Information used includes assumptions regarding the likelihood of collecting current and past due accounts, repossession rates, the recovery rate on the underlying collateral based on used truck values and other pledged collateral or recourse. The Company has developed a range of loss estimates for each of its country portfolios based on historical experience, taking into account loss frequency and severity in both strong and weak truck market conditions. A projection is made of the range of estimated credit losses inherent in the portfolio from which an amount is determined as probable based on current market conditions and other factors impacting the creditworthiness of the Company’s borrowers and their ability to repay. After determining the appropriate level of the allowance for credit losses, a provision for losses on finance receivables is charged to income as necessary to reflect management’s estimate of incurred credit losses, net of recoveries, inherent in the portfolio. In determining the fair value of the collateral, the Company uses a pricing matrix and categorizes the fair value as Level 2 in the hierarchy of fair value measurement. The pricing matrix is reviewed quarterly and updated as appropriate. The pricing matrix considers the make, model and year of the equipment as well as recent sales prices of comparable equipment through wholesale channels to the Company’s dealers (principal market). The fair value of the collateral also considers the overall condition of the equipment. Accounts are charged-off against the allowance for credit losses when, in the judgment of management, they are considered uncollectible, which generally occurs upon repossession of the collateral. Typically the timing between the repossession and charge-off is not significant. In cases where repossession is delayed (e.g., for legal proceedings), the Company records a partial charge-off. The charge-off is determined by comparing the fair value of the collateral, less cost to sell, to the recorded investment.
Product Support Liabilities	Product support liabilities are estimated future payments related to product warranties, optional extended warranties and repair and maintenance (R&M) contracts. 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. Specific terms and conditions vary depending on the product and the country of sale. Optional extended warranty and R&M contracts can be purchased for periods which generally range up to five years. Warranty expenses and reserves are estimated and recorded at the time products or contracts are sold based on historical data regarding the source, frequency and cost of claims, net of any recoveries. The Company periodically assesses the adequacy of its recorded liabilities and adjusts them as appropriate to reflect actual experience. Revenue from extended warranty and R&M contracts is deferred and recognized to income generally on a straight-line basis over the contract period. Warranty and R&M costs on these contracts are recognized as incurred.
Derivative Financial Instruments	As part of its risk management strategy, the Company enters into derivative contracts to hedge against interest rates and foreign currency risk. Certain derivative instruments designated as either cash flow hedges or fair value hedges are subject to hedge accounting. Derivative instruments that are not subject to hedge accounting are held as economic hedges. The Company’s policies prohibit the use of derivatives for speculation or trading. At the inception of each hedge relationship, the Company documents its risk management objectives, procedures and accounting treatment. All of the Company’s interest-rate and certain foreign-exchange contracts are transacted under International Swaps and Derivatives Association (ISDA) master agreements. Each agreement permits the net settlement of amounts owed in the event of default and certain other termination events. For derivative financial instruments, the Company has elected not to offset derivative positions in the balance sheet with the same counterparty under the same agreements and is not required to post or receive collateral. Exposure limits and minimum credit ratings are used to minimize the risks of counterparty default. The Company’s maximum exposure to potential default of its swap counterparties is limited to the asset position of its swap portfolio. The asset position of the Company’s swap portfolio is $90.3 at March 31, 2016. The Company uses regression analysis to assess effectiveness of interest-rate contracts on a quarterly basis. For foreign-exchange contracts, the Company performs quarterly assessments to ensure that critical terms continue to match. All components of the derivative instrument’s gain or loss are included in the assessment of hedge effectiveness. Gains or losses on the ineffective portion of cash flow hedges are recognized currently in earnings. Hedge accounting is discontinued prospectively when the Company determines that a derivative financial instrument has ceased to be a highly effective hedge.

Disclosure of accounting policy for major classes of inventories, bases of stating inventories (for example, lower of cost or market), methods by which amounts are added and removed from inventory classes (for example, FIFO, LIFO, or average cost), loss recognition on impairment of inventories, and situations in which inventories are stated above cost. If inventory is carried at cost, this disclosure includes the nature of the cost elements included in inventory.