Separate Financial Information of Subsidiary Guarantors of Indebtedness (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Condensed Consolidating Statements of Income
Net sales	$ 1,984.4	$ 2,062.3	$ 3,734.2	$ 3,930.8
Cost of sales	1,681.0	1,818.2	3,184.8	3,461.8
Gross income	303.4	244.1	549.4	469.0
Selling, general and administrative expenses	154.3	145.4	305.6	276.5
Amortization of purchased intangibles	14.5	14.6	28.9	29.3
Operating income	134.6	84.1	214.9	163.2
Interest expense	(16.4)	(18.0)	(32.8)	(38.5)
Interest income	1.7	0.6	4.2	1.2
Miscellaneous, net	0.1	1.3	0.4	(4.3)
Income from continuing operations before income taxes and equity in earnings of unconsolidated affiliates	120.0	68.0	186.7	121.6
Provision for income taxes	34.8	24.4	55.8	36.8
Income from continuing operations before equity in earnings of unconsolidated affiliates	85.2	43.6	130.9	84.8
Equity in earnings of consolidated subsidiaries	0	0	0	0
Equity in earnings (losses) of unconsolidated affiliates	0.7	0	1.3	0.7
Income from continuing operations, net of tax	85.9	43.6	132.2	85.5
Discontinued operations, net of tax	0.6	(5.6)	0.8	(8.2)
Net income	86.5	38.0	133.0	77.3
Net income attributable to noncontrolling interest	0	(0.7)	0	(1.1)
Net income attributable to Oshkosh Corporation	86.5	37.3	133.0	76.2
Oshkosh Corporation
Condensed Consolidating Statements of Income
Net sales	863.3	1,016.0	1,721.7	2,086.8
Cost of sales	771.2	944.7	1,540.4	1,895.4
Gross income	92.1	71.3	181.3	191.4
Selling, general and administrative expenses	64.0	56.3	135.8	110.9
Amortization of purchased intangibles	0	0	0.1	0.1
Operating income	28.1	15.0	45.4	80.4
Interest expense	(50.7)	(45.8)	(101.5)	(93.9)
Interest income	0.6	0.6	1.2	1.1
Miscellaneous, net	12.2	2.8	21.3	4.9
Income from continuing operations before income taxes and equity in earnings of unconsolidated affiliates	(9.8)	(27.4)	(33.6)	(7.5)
Provision for income taxes	(3.0)	(6.2)	(10.4)	(2.0)
Income from continuing operations before equity in earnings of unconsolidated affiliates	(6.8)	(21.2)	(23.2)	(5.5)
Equity in earnings of consolidated subsidiaries	93.3	58.7	156.2	81.9
Equity in earnings (losses) of unconsolidated affiliates	0	(0.2)	0	(0.2)
Income from continuing operations, net of tax	86.5	37.3	133.0	76.2
Discontinued operations, net of tax	0	0	0	0
Net income	86.5	37.3	133.0	76.2
Net income attributable to noncontrolling interest	0	0	0	0
Net income attributable to Oshkosh Corporation	86.5	37.3	133.0	76.2
Guarantor Subsidiaries
Condensed Consolidating Statements of Income
Net sales	908.0	847.4	1,639.5	1,582.1
Cost of sales	723.2	698.5	1,320.3	1,355.4
Gross income	184.8	148.9	319.2	226.7
Selling, general and administrative expenses	82.8	45.0	156.8	84.1
Amortization of purchased intangibles	10.0	10.0	19.9	20.0
Operating income	92.0	93.9	142.5	122.6
Interest expense	(14.0)	(19.7)	(28.0)	(39.1)
Interest income	9.1	7.6	19.1	15.1
Miscellaneous, net	(37.4)	(56.2)	(65.1)	(91.2)
Income from continuing operations before income taxes and equity in earnings of unconsolidated affiliates	49.7	25.6	68.5	7.4
Provision for income taxes	15.4	7.4	21.3	1.5
Income from continuing operations before equity in earnings of unconsolidated affiliates	34.3	18.2	47.2	5.9
Equity in earnings of consolidated subsidiaries	28.5	28.5	45.5	48.9
Equity in earnings (losses) of unconsolidated affiliates	0	0	0	0
Income from continuing operations, net of tax	62.8	46.7	92.7	54.8
Discontinued operations, net of tax	0.6	(5.2)	0.8	(7.7)
Net income	63.4	41.5	93.5	47.1
Net income attributable to noncontrolling interest	0	0	0	0
Net income attributable to Oshkosh Corporation	63.4	41.5	93.5	47.1
Non-Guarantor Subsidiaries
Condensed Consolidating Statements of Income
Net sales	250.5	249.6	440.7	462.1
Cost of sales	224.0	225.0	391.7	410.4
Gross income	26.5	24.6	49.0	51.7
Selling, general and administrative expenses	7.5	44.1	13.0	81.5
Amortization of purchased intangibles	4.5	4.6	8.9	9.2
Operating income	14.5	(24.1)	27.1	(39.0)
Interest expense	(0.8)	(1.2)	(1.9)	(2.2)
Interest income	41.1	41.1	82.5	81.7
Miscellaneous, net	25.3	54.7	44.2	82.0
Income from continuing operations before income taxes and equity in earnings of unconsolidated affiliates	80.1	70.5	151.9	122.5
Provision for income taxes	22.4	23.5	44.9	37.6
Income from continuing operations before equity in earnings of unconsolidated affiliates	57.7	47.0	107.0	84.9
Equity in earnings of consolidated subsidiaries	34.8	20.2	46.6	13.7
Equity in earnings (losses) of unconsolidated affiliates	0.7	0.2	1.3	0.9
Income from continuing operations, net of tax	93.2	67.4	154.9	99.5
Discontinued operations, net of tax	0	(0.4)	0	(0.5)
Net income	93.2	67.0	154.9	99.0
Net income attributable to noncontrolling interest	0	(0.7)	0	(1.1)
Net income attributable to Oshkosh Corporation	93.2	66.3	154.9	97.9
Eliminations
Condensed Consolidating Statements of Income
Net sales	(37.4)	(50.7)	(67.7)	(200.2)
Cost of sales	(37.4)	(50.0)	(67.6)	(199.4)
Gross income	0	(0.7)	(0.1)	(0.8)
Selling, general and administrative expenses	0	0	0	0
Amortization of purchased intangibles	0	0	0	0
Operating income	0	(0.7)	(0.1)	(0.8)
Interest expense	49.1	48.7	98.6	96.7
Interest income	(49.1)	(48.7)	(98.6)	(96.7)
Miscellaneous, net	0	0	0	0
Income from continuing operations before income taxes and equity in earnings of unconsolidated affiliates	0	(0.7)	(0.1)	(0.8)
Provision for income taxes	0	(0.3)	0	(0.3)
Income from continuing operations before equity in earnings of unconsolidated affiliates	0	(0.4)	(0.1)	(0.5)
Equity in earnings of consolidated subsidiaries	(156.6)	(107.4)	(248.3)	(144.5)
Equity in earnings (losses) of unconsolidated affiliates	0	0	0	0
Income from continuing operations, net of tax	(156.6)	(107.8)	(248.4)	(145.0)
Discontinued operations, net of tax	0	0	0	0
Net income	(156.6)	(107.8)	(248.4)	(145.0)
Net income attributable to noncontrolling interest	0	0	0	0
Net income attributable to Oshkosh Corporation	$ (156.6)	$ (107.8)	$ (248.4)	$ (145.0)