Amortized Cost Basis of Finance Receivables and Charge-offs by Credit Quality Indicator and Portfolio Class (Detail) - Financial Services - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans	$ 5,173.9	$ 4,428.5
Financing Receivable Originated In Current Fiscal Year	5,577.5	5,942.3
Financing Receivable, Originated One Year before Current Fiscal Year	4,188.0	3,587.6
Financing Receivable, Originated Two Years before Current Fiscal Year	2,482.9	1,888.0
Financing Receivable, Originated Three Years before Current Fiscal Year	1,173.4	1,038.2
Financing Receivable, Originated Four Years before Current Fiscal Year	468.8	444.3
Financed Receivables, By Origination Year, Prior	228.6	199.3
Finance Receivables, Total	19,293.1	17,528.2
Charge Offs Of Finance Receivables
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans		0.2
Financing Receivable Originated In Current Fiscal Year	1.0	1.5
Financing Receivable, Originated One Year before Current Fiscal Year	21.8	10.5
Financing Receivable, Originated Two Years before Current Fiscal Year	15.8	6.6
Financing Receivable, Originated Three Years before Current Fiscal Year	8.5	4.7
Financing Receivable, Originated Four Years before Current Fiscal Year	5.5	4.2
Financed Receivables, By Origination Year, Prior	8.6	0.9
Finance Receivables, Total	61.2	28.6
Dealer
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans	5,173.9	4,428.5
Financing Receivable Originated In Current Fiscal Year	682.8	789.1
Financing Receivable, Originated One Year before Current Fiscal Year	664.6	520.0
Financing Receivable, Originated Two Years before Current Fiscal Year	410.7	291.2
Financing Receivable, Originated Three Years before Current Fiscal Year	194.9	162.8
Financing Receivable, Originated Four Years before Current Fiscal Year	102.6	161.8
Financed Receivables, By Origination Year, Prior	142.0	125.2
Finance Receivables, Total	7,371.5	6,478.6
Dealer | Charge Offs Of Finance Receivables
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans		0.2
Finance Receivables, Total		0.2
Dealer | Wholesale
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans	4,944.1	4,147.8
Finance Receivables, Total	4,944.1	4,147.8
Dealer | Wholesale | Charge Offs Of Finance Receivables
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans		0.2
Finance Receivables, Total		0.2
Dealer | Wholesale | Performing
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans	4,936.1	4,129.8
Finance Receivables, Total	4,936.1	4,129.8
Dealer | Wholesale | Watch
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans	7.1	18.0
Finance Receivables, Total	7.1	18.0
Dealer | Wholesale | At-risk
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans	0.9
Finance Receivables, Total	0.9
Dealer | Retail
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans	229.8	280.7
Financing Receivable Originated In Current Fiscal Year	682.8	789.1
Financing Receivable, Originated One Year before Current Fiscal Year	664.6	520.0
Financing Receivable, Originated Two Years before Current Fiscal Year	410.7	291.2
Financing Receivable, Originated Three Years before Current Fiscal Year	194.9	162.8
Financing Receivable, Originated Four Years before Current Fiscal Year	102.6	161.8
Financed Receivables, By Origination Year, Prior	142.0	125.2
Finance Receivables, Total	2,427.4	2,330.8
Dealer | Retail | Performing
Financing Receivable, Recorded Investment [Line Items]
Financed Receivables, By Origination Year, Loans	229.8	280.7
Financing Receivable Originated In Current Fiscal Year	680.8	789.1
Financing Receivable, Originated One Year before Current Fiscal Year	641.5	520.0
Financing Receivable, Originated Two Years before Current Fiscal Year	404.6	291.2
Financing Receivable, Originated Three Years before Current Fiscal Year	192.8	162.8
Financing Receivable, Originated Four Years before Current Fiscal Year	98.0	161.8
Financed Receivables, By Origination Year, Prior	141.6	125.2
Finance Receivables, Total	2,389.1	2,330.8
Dealer | Retail | Watch
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	2.0
Financing Receivable, Originated One Year before Current Fiscal Year	23.1
Financing Receivable, Originated Two Years before Current Fiscal Year	6.1
Financing Receivable, Originated Three Years before Current Fiscal Year	2.1
Financing Receivable, Originated Four Years before Current Fiscal Year	4.6
Financed Receivables, By Origination Year, Prior	0.4
Finance Receivables, Total	38.3
Customer Retail
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	4,894.7	5,153.2
Financing Receivable, Originated One Year before Current Fiscal Year	3,523.4	3,067.6
Financing Receivable, Originated Two Years before Current Fiscal Year	2,072.2	1,596.8
Financing Receivable, Originated Three Years before Current Fiscal Year	978.5	875.4
Financing Receivable, Originated Four Years before Current Fiscal Year	366.2	282.5
Financed Receivables, By Origination Year, Prior	86.6	74.1
Finance Receivables, Total	11,921.6	11,049.6
Customer Retail | Charge Offs Of Finance Receivables
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year		1.5
Financing Receivable, Originated One Year before Current Fiscal Year		10.5
Financing Receivable, Originated Two Years before Current Fiscal Year		6.6
Financing Receivable, Originated Three Years before Current Fiscal Year		4.7
Financing Receivable, Originated Four Years before Current Fiscal Year		4.2
Financed Receivables, By Origination Year, Prior		0.9
Finance Receivables, Total		28.4
Customer Retail | Fleet
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	4,367.2	4,689.7
Financing Receivable, Originated One Year before Current Fiscal Year	3,205.8	2,730.2
Financing Receivable, Originated Two Years before Current Fiscal Year	1,855.8	1,329.9
Financing Receivable, Originated Three Years before Current Fiscal Year	829.6	730.5
Financing Receivable, Originated Four Years before Current Fiscal Year	306.3	229.2
Financed Receivables, By Origination Year, Prior	73.4	65.1
Finance Receivables, Total	10,638.1	9,774.6
Customer Retail | Fleet | Charge Offs Of Finance Receivables
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	0.9	1.0
Financing Receivable, Originated One Year before Current Fiscal Year	19.4	9.4
Financing Receivable, Originated Two Years before Current Fiscal Year	12.1	5.1
Financing Receivable, Originated Three Years before Current Fiscal Year	7.5	4.2
Financing Receivable, Originated Four Years before Current Fiscal Year	4.2	4.2
Financed Receivables, By Origination Year, Prior	7.8	0.6
Finance Receivables, Total	51.9	24.5
Customer Retail | Fleet | Performing
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	4,306.5	4,601.7
Financing Receivable, Originated One Year before Current Fiscal Year	2,991.4	2,667.2
Financing Receivable, Originated Two Years before Current Fiscal Year	1,761.1	1,309.5
Financing Receivable, Originated Three Years before Current Fiscal Year	781.9	719.2
Financing Receivable, Originated Four Years before Current Fiscal Year	298.2	226.7
Financed Receivables, By Origination Year, Prior	71.0	64.1
Finance Receivables, Total	10,210.1	9,588.4
Customer Retail | Fleet | Watch
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	11.2	46.0
Financing Receivable, Originated One Year before Current Fiscal Year	17.6	32.0
Financing Receivable, Originated Two Years before Current Fiscal Year	13.9	7.5
Financing Receivable, Originated Three Years before Current Fiscal Year	5.8	5.7
Financing Receivable, Originated Four Years before Current Fiscal Year	2.1	1.3
Financed Receivables, By Origination Year, Prior	0.9	0.9
Finance Receivables, Total	51.5	93.4
Customer Retail | Fleet | At-risk
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	49.5	42.0
Financing Receivable, Originated One Year before Current Fiscal Year	196.8	31.0
Financing Receivable, Originated Two Years before Current Fiscal Year	80.8	12.9
Financing Receivable, Originated Three Years before Current Fiscal Year	41.9	5.6
Financing Receivable, Originated Four Years before Current Fiscal Year	6.0	1.2
Financed Receivables, By Origination Year, Prior	1.5	0.1
Finance Receivables, Total	376.5	92.8
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	527.5	463.5
Financing Receivable, Originated One Year before Current Fiscal Year	317.6	337.4
Financing Receivable, Originated Two Years before Current Fiscal Year	216.4	266.9
Financing Receivable, Originated Three Years before Current Fiscal Year	148.9	144.9
Financing Receivable, Originated Four Years before Current Fiscal Year	59.9	53.3
Financed Receivables, By Origination Year, Prior	13.2	9.0
Finance Receivables, Total	1,283.5	1,275.0
Customer Retail | Owner/Operator | Charge Offs Of Finance Receivables
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	0.1	0.5
Financing Receivable, Originated One Year before Current Fiscal Year	2.4	1.1
Financing Receivable, Originated Two Years before Current Fiscal Year	3.7	1.5
Financing Receivable, Originated Three Years before Current Fiscal Year	1.0	0.5
Financing Receivable, Originated Four Years before Current Fiscal Year	1.3
Financed Receivables, By Origination Year, Prior	0.8	0.3
Finance Receivables, Total	9.3	3.9
Customer Retail | Owner/Operator | Performing
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	524.1	460.9
Financing Receivable, Originated One Year before Current Fiscal Year	303.7	332.9
Financing Receivable, Originated Two Years before Current Fiscal Year	206.2	263.6
Financing Receivable, Originated Three Years before Current Fiscal Year	145.1	142.1
Financing Receivable, Originated Four Years before Current Fiscal Year	57.6	52.8
Financed Receivables, By Origination Year, Prior	12.7	8.6
Finance Receivables, Total	1,249.4	1,260.9
Customer Retail | Owner/Operator | Watch
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	2.5	2.0
Financing Receivable, Originated One Year before Current Fiscal Year	12.1	3.2
Financing Receivable, Originated Two Years before Current Fiscal Year	8.0	2.2
Financing Receivable, Originated Three Years before Current Fiscal Year	2.9	1.3
Financing Receivable, Originated Four Years before Current Fiscal Year	1.3	0.3
Financed Receivables, By Origination Year, Prior	0.4
Finance Receivables, Total	27.2	9.0
Customer Retail | Owner/Operator | At-risk
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable Originated In Current Fiscal Year	0.9	0.6
Financing Receivable, Originated One Year before Current Fiscal Year	1.8	1.3
Financing Receivable, Originated Two Years before Current Fiscal Year	2.2	1.1
Financing Receivable, Originated Three Years before Current Fiscal Year	0.9	1.5
Financing Receivable, Originated Four Years before Current Fiscal Year	1.0	0.2
Financed Receivables, By Origination Year, Prior	0.1	0.4
Finance Receivables, Total	$ 6.9	$ 5.1