Other Comprehensive Income (Loss) - Schedule of changes in accumulated other comprehensive income (loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss), before Tax [Roll Forward]
Balance at the beginning of the period	$ (155.6)
Other comprehensive income before reclassifications
Before tax amount	47.7	$ 2.8
Tax expense	(1.3)	(0.1)
After tax amount	46.4	2.7
Amounts reclassified from accumulated other comprehensive loss (2)	0.1	1.1
Total changes in other comprehensive income, net of tax	46.5	3.8
Balance at the end of the period	(108.9)
Pension and Postretirement
Accumulated Other Comprehensive Income (Loss), before Tax [Roll Forward]
Balance at the beginning of the period	(32.8)	(49.2)
Other comprehensive income before reclassifications
Before tax amount	0.0	0.0
Tax expense	0.0	0.0
After tax amount	0.0	0.0
Amounts reclassified from accumulated other comprehensive loss (2)	(0.2)	0.7
Total changes in other comprehensive income, net of tax	(0.2)	0.7
Balance at the end of the period	(33.0)	(48.5)
Currency Translation (1)
Accumulated Other Comprehensive Income (Loss), before Tax [Roll Forward]
Balance at the beginning of the period	(113.7)	13.1
Other comprehensive income before reclassifications
Before tax amount	43.2	2.5
Tax expense	0.0	0.0
After tax amount	43.2	2.5
Amounts reclassified from accumulated other comprehensive loss (2)	0.0	0.0
Total changes in other comprehensive income, net of tax	43.2	2.5
Balance at the end of the period	(70.5)	15.6
Net Unrealized (Loss) Gain on Derivative Instruments
Accumulated Other Comprehensive Income (Loss), before Tax [Roll Forward]
Balance at the beginning of the period	(9.1)	(10.2)
Other comprehensive income before reclassifications
Before tax amount	4.7	0.4
Tax expense	(1.3)	(0.1)
After tax amount	3.4	0.3
Amounts reclassified from accumulated other comprehensive loss (2)	0.3	0.4
Total changes in other comprehensive income, net of tax	3.7	0.7
Balance at the end of the period	(5.4)	(9.5)
Total Attributable to Hillenbrand, Inc.
Accumulated Other Comprehensive Income (Loss), before Tax [Roll Forward]
Balance at the beginning of the period	(155.6)	(46.3)
Other comprehensive income before reclassifications
Before tax amount	47.9	2.9
Tax expense	(1.3)	(0.1)
After tax amount	46.6	2.8
Amounts reclassified from accumulated other comprehensive loss (2)	0.1	1.1
Total changes in other comprehensive income, net of tax	46.7	3.9
Balance at the end of the period	(108.9)	(42.4)
Noncontrolling Interests
Other comprehensive income before reclassifications
Before tax amount	(0.2)	(0.1)
Tax expense	0.0	0.0
After tax amount	(0.2)	(0.1)
Amounts reclassified from accumulated other comprehensive loss (2)	0.0	0.0
Total changes in other comprehensive income, net of tax	$ (0.2)	$ (0.1)