Business Segment Information - Schedule of Net Sales by Geographical Segments (Details) - USD ($) $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2022	[1]	Sep. 30, 2022	[2]	Jun. 30, 2022	Mar. 31, 2022	[3]	Dec. 31, 2021	Sep. 30, 2021	[4]	Jun. 30, 2021	[5]	Mar. 31, 2021	[6]	Dec. 31, 2020	[7]	Dec. 31, 2022	Sep. 30, 2021	Sep. 30, 2020
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	$ 2,203.6		$ 2,066.7		$ 2,066.0	$ 1,945.7		$ 1,791.7	$ 2,063.0		$ 2,208.8		$ 1,889.0		$ 1,576.5		$ 8,282.0	$ 7,737.3	$ 6,856.8
North America
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								1,611.3									7,468.2	6,748.5	6,023.7
Europe, Africa and Middle East
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								99.0									455.2	504.8	413.7
Rest of the World
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								81.4									358.6	484.0	419.4
Operating Segments
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								1,791.7									8,282.0	7,737.3	6,856.8
Intersegment Eliminations
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								(2.5)									(7.1)	(24.6)	(34.6)
Intersegment Eliminations | North America
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								(2.5)									(7.1)	(24.6)	(34.6)
Access Equipment
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								833.3									3,971.9	3,067.3	2,505.7
Access Equipment | Operating Segments
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								833.5									3,972.1	3,072.1	2,515.1
Access Equipment | Operating Segments | North America
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								671.6									3,298.9	2,358.9	1,881.6
Access Equipment | Operating Segments | Europe, Africa and Middle East
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								86.1									353.0	273.4	275.3
Access Equipment | Operating Segments | Rest of the World
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								75.8									320.2	439.8	358.2
Access Equipment | Intersegment Eliminations
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								0.2									0.2	4.8	9.4
Defense
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								531.1									2,139.9	2,524.1	2,300.4
Defense | Operating Segments
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								531.5									2,141.3	2,525.6	2,311.5
Defense | Operating Segments | North America
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								523.4									2,047.5	2,337.8	2,200.4
Defense | Operating Segments | Europe, Africa and Middle East
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								8.0									92.7	183.2	107.0
Defense | Operating Segments | Rest of the World
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								0.1									1.1	4.6	4.1
Defense | Intersegment Eliminations
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								0.4									1.4	1.5	11.1
Fire & Emergency
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								217.0									1,108.2	1,211.6	1,098.0
Fire & Emergency | Operating Segments
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								218.6									1,111.6	1,226.6	1,107.0
Fire & Emergency | Operating Segments | North America
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								211.9									1,075.6	1,147.4	1,029.3
Fire & Emergency | Operating Segments | Europe, Africa and Middle East
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								4.1									7.4	46.7	29.8
Fire & Emergency | Operating Segments | Rest of the World
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								2.6									28.6	32.5	47.9
Fire & Emergency | Intersegment Eliminations
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								1.6									3.4	15.0	9.0
Commercial
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								210.2									1,061.8	933.6	951.3
Commercial | Operating Segments
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								210.6									1,064.1	937.6	957.8
Commercial | Operating Segments | North America
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								206.9									1,053.3	929.0	947.0
Commercial | Operating Segments | Europe, Africa and Middle East
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								0.8									2.1	1.5	1.6
Commercial | Operating Segments | Rest of the World
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								2.9									8.7	7.1	9.2
Commercial | Intersegment Eliminations
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues								$ 0.4									$ 2.3	$ 4.0	$ 6.5

[1] The fourth quarter of fiscal 2022 was impacted by a $5.6 million ($4.3 million after-tax) intangible asset impairment charge in the Defense segment and a $33.6 million ($25.7 million after-tax) pension settlement charge.

[2] The third quarter of fiscal 2022 was impacted by expense of $4.6 million to eliminate cumulative translation adjustments upon liquidation of foreign entities in the Access Equipment segment and a $2.1 million intangible asset impairment charge in the Commercial segment.

[3] The first quarter of fiscal 2022 was impacted by tax expense of $18.1 million for anti-hybrid tax on prior period income.

[4] The fourth quarter of the year ended September 30, 2021 was impacted by a tax benefit of $11.7 million for the revaluation of deferred tax liabilities and a tax benefit of $5.4 million for net operating loss carrybacks.

[5] The third quarter of the year ended September 30, 2021 was impacted a tax benefit of $69.9 million for net operating loss carrybacks and $1.3 million ($1.4 million after-tax) of restructuring-related costs in the Access Equipment segment.

[6] The second quarter of the year ended September 30, 2021 was impacted by $2.2 million ($2.5 million after-tax) of restructuring-related costs in the Access Equipment segment.

[7] The first quarter of the year ended September 30, 2021 was impacted by $8.0 million ($7.8 million after-tax) of restructuring-related costs in the Access Equipment segment.