CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Statement of Comprehensive Income [Abstract]
Net income	$ 81.6	$ 61.0	$ 278.8	$ 134.1
Other comprehensive income (loss), net of tax:
Foreign currency translation	13.0	92.4	7.9	59.2
Derivative financial instruments	1.3	(21.7)	0.4	8.6
Minimum pension liabilities	0.8	(3.4)	2.9	(1.3)
Other comprehensive income (loss), net of tax	15.1	67.3	11.2	66.5
Comprehensive income	96.7	128.3	290.0	200.6
Comprehensive income attributable to noncontrolling interests	3.9	6.6	13.4	17.5
Comprehensive income attributable to Greif, Inc.	$ 92.8	$ 121.7	$ 276.6	$ 183.1