CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME Statement (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 309.3	$ 318.0	$ 231.9
Other comprehensive income (loss), net of tax:
Change in fair value of derivative instruments	0	0	1.4
Employee pension and postretirement benefits	(21.2)	76.6	31.1
Currency translation adjustments	(33.4)	10.2	(11.3)
Net current period other comprehensive income (loss)	(54.6)	86.8	21.2
Comprehensive income	254.7	404.8	253.1
Comprehensive income attributable to noncontrolling interest	0	0	(1.1)
Comprehensive income attributable to Oshkosh Corporation	$ 254.7	$ 404.8	$ 252.0