Separate Financial Information of Subsidiary Guarantors of Indebtedness (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Condensed Consolidating Statements of Income
Net sales	$ 1,211.4	$ 1,252.0
Cost of sales	1,011.7	1,069.2
Gross income	199.7	182.8
Selling, general and administrative	151.0	139.3
Amortization of purchased intangibles	12.5	13.2
Operating income	36.2	30.3
Interest expense	(14.7)	(14.6)
Interest income	0.8	0.5
Miscellaneous, net	1.3	0.0
Income before income taxes and equity in earnings of unconsolidated affiliates	23.6	16.2
Provision for income taxes	5.2	1.7
Income before equity in earnings of unconsolidated affiliates	18.4	14.5
Equity in earnings of consolidated subsidiaries	0.0	0.0
Equity in earnings of unconsolidated affiliates	0.8	0.1
Net income	19.2	14.6
Other comprehensive income (loss), net of tax	(29.6)	(10.5)
Comprehensive income (loss)	(10.4)	4.1
Oshkosh Corporation
Condensed Consolidating Statements of Income
Net sales	0.0	0.0
Cost of sales	(0.8)	0.3
Gross income	0.8	(0.3)
Selling, general and administrative	31.6	23.6
Amortization of purchased intangibles	0.0	0.0
Operating income	(30.8)	(23.9)
Interest expense	(13.6)	(59.6)
Interest income	0.7	0.5
Miscellaneous, net	22.5	14.9
Income before income taxes and equity in earnings of unconsolidated affiliates	(21.2)	(68.1)
Provision for income taxes	(5.1)	(5.8)
Income before equity in earnings of unconsolidated affiliates	(16.1)	(62.3)
Equity in earnings of consolidated subsidiaries	35.3	77.2
Equity in earnings of unconsolidated affiliates	0.0	(0.3)
Net income	19.2	14.6
Other comprehensive income (loss), net of tax	(29.6)	(10.5)
Comprehensive income (loss)	(10.4)	4.1
Guarantor Subsidiaries
Condensed Consolidating Statements of Income
Net sales	1,049.8	1,056.8
Cost of sales	874.5	899.0
Gross income	175.3	157.8
Selling, general and administrative	91.5	89.3
Amortization of purchased intangibles	9.6	9.8
Operating income	74.2	58.7
Interest expense	(13.6)	(14.7)
Interest income	4.1	16.2
Miscellaneous, net	(52.2)	(41.4)
Income before income taxes and equity in earnings of unconsolidated affiliates	12.5	18.8
Provision for income taxes	3.0	1.6
Income before equity in earnings of unconsolidated affiliates	9.5	17.2
Equity in earnings of consolidated subsidiaries	15.7	18.1
Equity in earnings of unconsolidated affiliates	0.0	0.0
Net income	25.2	35.3
Other comprehensive income (loss), net of tax	(0.9)	(2.9)
Comprehensive income (loss)	24.3	32.4
Non-Guarantor Subsidiaries
Condensed Consolidating Statements of Income
Net sales	202.9	220.4
Cost of sales	179.5	195.1
Gross income	23.4	25.3
Selling, general and administrative	27.9	26.4
Amortization of purchased intangibles	2.9	3.4
Operating income	(7.4)	(4.5)
Interest expense	(0.5)	(0.7)
Interest income	9.0	44.2
Miscellaneous, net	31.0	26.5
Income before income taxes and equity in earnings of unconsolidated affiliates	32.1	65.5
Provision for income taxes	7.2	5.9
Income before equity in earnings of unconsolidated affiliates	24.9	59.6
Equity in earnings of consolidated subsidiaries	(10.7)	(6.4)
Equity in earnings of unconsolidated affiliates	0.8	0.4
Net income	15.0	53.6
Other comprehensive income (loss), net of tax	(29.2)	(8.1)
Comprehensive income (loss)	(14.2)	45.5
Eliminations
Condensed Consolidating Statements of Income
Net sales	(41.3)	(25.2)
Cost of sales	(41.5)	(25.2)
Gross income	0.2	0.0
Selling, general and administrative	0.0	0.0
Amortization of purchased intangibles	0.0	0.0
Operating income	0.2	0.0
Interest expense	13.0	60.4
Interest income	(13.0)	(60.4)
Miscellaneous, net	0.0	0.0
Income before income taxes and equity in earnings of unconsolidated affiliates	0.2	0.0
Provision for income taxes	0.1	0.0
Income before equity in earnings of unconsolidated affiliates	0.1	0.0
Equity in earnings of consolidated subsidiaries	(40.3)	(88.9)
Equity in earnings of unconsolidated affiliates	0.0	0.0
Net income	(40.2)	(88.9)
Other comprehensive income (loss), net of tax	30.1	11.0
Comprehensive income (loss)	$ (10.1)	$ (77.9)