CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 180.9	$ 26.7
Other comprehensive income (loss), net of tax:
Foreign currency translation	12.3	(94.0)
Derivative financial instruments	(0.8)	51.5
Minimum pension liabilities	0.4	3.5
Other comprehensive income (loss), net of tax	11.9	(39.0)
Comprehensive income (loss)	192.8	(12.3)
Comprehensive income attributable to noncontrolling interests	6.3	3.9
Comprehensive income (loss) attributable to Greif, Inc.	$ 186.5	$ (16.2)