Separate Financial Information of Subsidiary Guarantors of Indebtedness (Details 3) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Current assets:
Cash and cash equivalents	$ 455.7	$ 540.7	$ 440.3	$ 428.5
Receivables, net	646.2	1,018.6
Inventories, net	1,056.9	937.5
Other current assets	211.4	197.7
Total current assets	2,370.2	2,694.5
Investment in and advances to consolidated subsidiaries	0	0
Intangible assets, net	1,800.9	1,809.2
Other long-term assets	432.8	444.1
Total assets	4,603.9	4,947.8
Current liabilities:
Accounts payable	532.6	683.3
Customer advances	481.7	510.4
Other current liabilities	422.6	510.8
Total current liabilities	1,436.9	1,704.5
Long-term debt, less current maturities	938.7	955.0
Other long-term liabilities	440.4	434.8
Oshkosh Corporation shareholders' equity	1,787.9	1,853.5
Total liabilities and shareholders' equity	4,603.9	4,947.8
Oshkosh Corporation
Current assets:
Cash and cash equivalents	423.7	500.0	363.9	376.3
Receivables, net	202.9	388.0
Inventories, net	395.0	284.3
Other current assets	148.4	129.2
Total current assets	1,170.0	1,301.5
Investment in and advances to consolidated subsidiaries	2,301.1	2,358.1
Intangible assets, net	2.4	2.5
Other long-term assets	149.8	154.7
Total assets	3,623.3	3,816.8
Current liabilities:
Accounts payable	292.2	326.2
Customer advances	291.8	315.4
Other current liabilities	148.3	213.6
Total current liabilities	732.3	855.2
Long-term debt, less current maturities	938.7	955.0
Other long-term liabilities	164.4	153.1
Oshkosh Corporation shareholders' equity	1,787.9	1,853.5
Total liabilities and shareholders' equity	3,623.3	3,816.8
Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	3.2	5.5	26.6	13.5
Receivables, net	349.3	487.5
Inventories, net	420.7	415.7
Other current assets	42.7	47.9
Total current assets	815.9	956.6
Investment in and advances to consolidated subsidiaries	(1,132.9)	(1,182.9)
Intangible assets, net	1,100.5	1,110.4
Other long-term assets	151.2	156.8
Total assets	934.7	1,040.9
Current liabilities:
Accounts payable	176.8	288.9
Customer advances	186.0	190.5
Other current liabilities	205.0	220.2
Total current liabilities	567.8	699.6
Long-term debt, less current maturities	0	0
Other long-term liabilities	132.7	137.3
Oshkosh Corporation shareholders' equity	234.2	204.0
Total liabilities and shareholders' equity	934.7	1,040.9
Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	28.8	35.2	49.8	38.7
Receivables, net	133.6	177.3
Inventories, net	242.7	239.3
Other current assets	19.9	20.6
Total current assets	425.0	472.4
Investment in and advances to consolidated subsidiaries	3,343.3	3,235.8
Intangible assets, net	698.0	696.3
Other long-term assets	131.8	132.6
Total assets	4,598.1	4,537.1
Current liabilities:
Accounts payable	96.5	96.7
Customer advances	3.9	4.5
Other current liabilities	77.1	84.5
Total current liabilities	177.5	185.7
Long-term debt, less current maturities	0	0
Other long-term liabilities	143.3	144.4
Oshkosh Corporation shareholders' equity	4,277.3	4,207.0
Total liabilities and shareholders' equity	4,598.1	4,537.1
Eliminations
Current assets:
Cash and cash equivalents	0	0	0	0
Receivables, net	(39.6)	(34.2)
Inventories, net	(1.5)	(1.8)
Other current assets	0.4	0
Total current assets	(40.7)	(36.0)
Investment in and advances to consolidated subsidiaries	(4,511.5)	(4,411.0)
Intangible assets, net	0	0
Other long-term assets	0	0
Total assets	(4,552.2)	(4,447.0)
Current liabilities:
Accounts payable	(32.9)	(28.5)
Customer advances	0	0
Other current liabilities	(7.8)	(7.5)
Total current liabilities	(40.7)	(36.0)
Long-term debt, less current maturities	0	0
Other long-term liabilities	0	0
Oshkosh Corporation shareholders' equity	(4,511.5)	(4,411.0)
Total liabilities and shareholders' equity	$ (4,552.2)	$ (4,447.0)