Separate Financial Information of Subsidiary Guarantors of Indebtedness (Details 2) - USD ($) $ in Millions	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015
Current assets:
Cash and cash equivalents	$ 413.4	$ 321.9	$ 38.4	$ 42.9
Receivables, net	945.1	1,021.9
Inventories, net	1,455.1	979.8
Other current assets	90.1	93.9
Total current assets	2,903.7	2,417.5
Investment in and advances to consolidated subsidiaries	0.0	0.0
Intercompany receivables	0.0	0.0
Intangible assets, net	1,524.1	1,557.0
Other long-term assets	561.0	539.3
Total assets	4,988.8	4,513.8
Current liabilities:
Accounts payable	694.6	466.1
Customer advances	672.0	471.8
Other current liabilities	426.7	429.7
Total current liabilities	1,793.3	1,367.6
Long-term debt, less current maturities	817.1	826.2
Intercompany payables	0.0	0.0
Other long-term liabilities	345.1	343.5
Total shareholders' equity	2,033.3	1,976.5
Total liabilities and shareholders' equity	4,988.8	4,513.8
Reportable legal entities | Oshkosh Corporation
Current assets:
Cash and cash equivalents	373.5	285.4	5.8	14.8
Receivables, net	30.2	13.0
Inventories, net	0.0	0.0
Other current assets	31.5	28.0
Total current assets	435.2	326.4
Investment in and advances to consolidated subsidiaries	2,816.1	6,148.2
Intercompany receivables	48.0	48.0
Intangible assets, net	0.0	0.0
Other long-term assets	82.6	87.3
Total assets	3,381.9	6,609.9
Current liabilities:
Accounts payable	15.8	13.3
Customer advances	0.0	0.0
Other current liabilities	80.2	85.5
Total current liabilities	96.0	98.8
Long-term debt, less current maturities	817.1	826.2
Intercompany payables	364.2	3,639.4
Other long-term liabilities	71.3	69.0
Total shareholders' equity	2,033.3	1,976.5
Total liabilities and shareholders' equity	3,381.9	6,609.9
Reportable legal entities | Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	2.7	1.7	4.8	6.3
Receivables, net	725.8	734.3
Inventories, net	1,002.9	679.1
Other current assets	50.3	58.5
Total current assets	1,781.7	1,473.6
Investment in and advances to consolidated subsidiaries	1,282.4	1,253.6
Intercompany receivables	343.2	1,353.7
Intangible assets, net	928.2	947.5
Other long-term assets	227.8	232.7
Total assets	4,563.3	5,261.1
Current liabilities:
Accounts payable	571.9	375.0
Customer advances	668.0	465.8
Other current liabilities	247.6	246.5
Total current liabilities	1,487.5	1,087.3
Long-term debt, less current maturities	0.0	0.0
Intercompany payables	1,787.0	2,346.5
Other long-term liabilities	148.8	147.9
Total shareholders' equity	1,140.0	1,679.4
Total liabilities and shareholders' equity	4,563.3	5,261.1
Reportable legal entities | Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	37.2	34.8	27.8	21.8
Receivables, net	233.2	319.6
Inventories, net	452.2	300.7
Other current assets	8.3	7.4
Total current assets	730.9	662.5
Investment in and advances to consolidated subsidiaries	(104.8)	(120.0)
Intercompany receivables	1,808.0	4,632.2
Intangible assets, net	595.9	609.5
Other long-term assets	250.6	219.3
Total assets	3,280.6	6,003.5
Current liabilities:
Accounts payable	150.8	122.6
Customer advances	4.0	6.0
Other current liabilities	99.1	97.9
Total current liabilities	253.9	226.5
Long-term debt, less current maturities	0.0	0.0
Intercompany payables	48.0	48.0
Other long-term liabilities	125.0	126.6
Total shareholders' equity	2,853.7	5,602.4
Total liabilities and shareholders' equity	3,280.6	6,003.5
Eliminations
Current assets:
Cash and cash equivalents	0.0	0.0	$ 0.0	$ 0.0
Receivables, net	(44.1)	(45.0)
Inventories, net	0.0	0.0
Other current assets	0.0	0.0
Total current assets	(44.1)	(45.0)
Investment in and advances to consolidated subsidiaries	(3,993.7)	(7,281.8)
Intercompany receivables	(2,199.2)	(6,033.9)
Intangible assets, net	0.0	0.0
Other long-term assets	0.0	0.0
Total assets	(6,237.0)	(13,360.7)
Current liabilities:
Accounts payable	(43.9)	(44.8)
Customer advances	0.0	0.0
Other current liabilities	(0.2)	(0.2)
Total current liabilities	(44.1)	(45.0)
Long-term debt, less current maturities	0.0	0.0
Intercompany payables	(2,199.2)	(6,033.9)
Other long-term liabilities	0.0	0.0
Total shareholders' equity	(3,993.7)	(7,281.8)
Total liabilities and shareholders' equity	$ (6,237.0)	$ (13,360.7)