CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS’ EQUITY (UNAUDITED) - USD ($) shares in Thousands, $ in Millions	Total	Greif, Inc. Equity	Common Stock	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non controlling interests
Beginning balance (in shares) at Sep. 30, 2024			47,181
Beginning balance at Sep. 30, 2024	$ 2,134.3	$ 2,088.3	$ 229.7	$ (279.0)	$ 2,485.2	$ (347.6)	$ 46.0
Beginning balance (in shares) at Sep. 30, 2024				29,661
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	26.7	22.0			22.0		4.7
Other comprehensive income (loss):
Foreign currency translation, net of income tax expense	(94.0)	(93.2)				(93.2)	(0.8)
Derivative financial instruments, net of income tax expense (benefit)	51.5	51.5				51.5
Minimum pension liability adjustment, net of income tax benefit	3.5	3.5				3.5
Comprehensive income (loss)	(12.3)	(16.2)
Current period mark to redemption value of redeemable noncontrolling interest and other	(2.6)	(2.6)			(2.6)
Net income allocated to redeemable noncontrolling interests	(1.9)						(1.9)
Dividends paid to Greif, Inc. shareholders	(31.0)	(31.0)			(31.0)
Dividends paid to noncontrolling interests and other	(10.9)						(10.9)
Dividends earned on RSU shares	(0.2)	(0.2)			(0.2)
Colleague stock purchase plan	0.2	0.2	0.2
Share based compensation	1.5	1.5	$ 1.5
Ending balance (in shares) at Dec. 31, 2024			47,181
Ending balance at Dec. 31, 2024	2,077.1	2,040.0	$ 231.4	$ (279.0)	2,473.4	(385.8)	37.1
Ending balance (in shares) at Dec. 31, 2024				29,661
Beginning balance (in shares) at Sep. 30, 2025			47,501
Beginning balance at Sep. 30, 2025	2,952.4	2,914.9	$ 247.3	$ (276.5)	3,194.9	(250.8)	37.5
Beginning balance (in shares) at Sep. 30, 2025				29,341
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	180.9	174.6			174.6		6.3
Other comprehensive income (loss):
Foreign currency translation, net of income tax expense	12.3	12.3				12.3
Derivative financial instruments, net of income tax expense (benefit)	(0.8)	(0.8)				(0.8)
Minimum pension liability adjustment, net of income tax benefit	0.4	0.4				0.4
Comprehensive income (loss)	192.8	186.5
Current period mark to redemption value of redeemable noncontrolling interest and other	(0.6)	(0.6)			(0.6)
Net income allocated to redeemable noncontrolling interests	(1.4)						(1.4)
Dividends paid to Greif, Inc. shareholders	(31.7)	(31.7)			(31.7)
Dividends paid to noncontrolling interests and other	(5.0)						(5.0)
Dividends earned on RSU shares	(0.1)	(0.1)			(0.1)
Colleague stock purchase plan	0.3	0.3	$ 0.3
Share repurchases (in shares)			(1,924)	1,924
Share repurchases	(129.4)	(129.4)	$ 0.5	$ (129.9)
Share based compensation	1.2	1.2	$ 1.2
Ending balance (in shares) at Dec. 31, 2025			45,577
Ending balance at Dec. 31, 2025	$ 2,978.5	$ 2,941.1	$ 249.3	$ (406.4)	$ 3,337.1	$ (238.9)	$ 37.4
Ending balance (in shares) at Dec. 31, 2025				31,265