CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025
Net sales	$ 1,072.8	$ 1,078.4	$ 2,067.6	$ 2,095.1
Cost of products sold	825.8	829.9	1,618.0	1,647.2
Gross profit	247.0	248.5	449.6	447.9
Selling, general and administrative expenses	191.7	159.9	337.8	320.1
Acquisition and integration related costs	1.4	1.3	2.1	4.1
Restructuring and other charges	15.7	9.1	29.9	12.4
Non-cash asset impairment charges	4.5	17.2	4.7	17.5
(Gain) loss on disposal of properties, plants and equipment, net	(1.7)	0.1	(217.4)	(2.3)
Loss on disposal of businesses, net	0.0	0.2	0.5	1.3
Operating profit	35.4	60.7	292.0	94.8
Interest expense, net	10.0	15.5	19.7	31.4
Non-cash pension settlement charges	0.7	0.0	1.6	0.0
Debt extinguishment charges	2.5	0.0	2.5	0.0
Other expense, net	0.4	0.2	4.8	1.1
Income from continuing operations before income tax expense and equity earnings of unconsolidated affiliates, net	21.8	45.0	263.4	62.3
Income tax expense	5.9	20.0	64.8	26.8
Equity earnings of unconsolidated affiliates, net of tax	(0.4)	(0.1)	(0.6)	(0.9)
Net income from continuing operations	16.3	25.1	199.2	36.4
Net income (loss) from discontinued operations, net of tax	0.0	21.3	(2.0)	36.7
Net income	16.3	46.4	197.2	73.1
Net income attributable to noncontrolling interests	(3.7)	(6.5)	(10.0)	(11.2)
Net income attributable to Greif, Inc.	$ 12.6	$ 39.9	$ 187.2	$ 61.9
Class A Common Stock
Basic earnings per share attributable to Greif, Inc. common shareholders:
Class A and Class B common stock (continued operations) - basic (in usd per share)	$ 0.22	$ 0.32	$ 3.31	$ 0.44
Class A and Class B common stock (discontinued operations) - basic (in usd per share)	0	0.37	(0.03)	0.63
Earnings per Class A and Class B common stock - basic (in usd per share)	0.22	0.69	3.28	1.07
Diluted earnings per share attributable to Greif, Inc. common shareholders:
Class A and Class B common stock (continued operations) - diluted (in usd per share)	0.22	0.32	3.27	0.44
Class A and Class B common stock (discontinued operations) - diluted (in usd per share)	0	0.37	(0.03)	0.63
Earnings per Class A and Class B common stock - diluted (in usd per share)	$ 0.22	$ 0.69	$ 3.24	$ 1.07
Weighted-average number of Class A and Class B common shares outstanding:
Basic (in shares)	24,723,479	26,078,625	25,211,171	25,964,448
Diluted (in shares)	24,723,479	26,078,625	25,617,452	25,964,448
Cash dividends declared per common share:
Cash dividends declared per common share (in usd per share)	$ 0.56	$ 0.54	$ 1.12	$ 1.08
Class B Common Stock
Basic earnings per share attributable to Greif, Inc. common shareholders:
Class A and Class B common stock (continued operations) - basic (in usd per share)	0.33	0.48	4.95	0.65
Class A and Class B common stock (discontinued operations) - basic (in usd per share)	0	0.55	(0.05)	0.95
Earnings per Class A and Class B common stock - basic (in usd per share)	0.33	1.03	4.90	1.60
Diluted earnings per share attributable to Greif, Inc. common shareholders:
Class A and Class B common stock (continued operations) - diluted (in usd per share)	0.33	0.48	4.95	0.65
Class A and Class B common stock (discontinued operations) - diluted (in usd per share)	0	0.55	(0.05)	0.95
Earnings per Class A and Class B common stock - diluted (in usd per share)	$ 0.33	$ 1.03	$ 4.90	$ 1.60
Weighted-average number of Class A and Class B common shares outstanding:
Basic (in shares)	21,485,063	21,331,127	21,400,064	21,331,127
Diluted (in shares)	21,485,063	21,331,127	21,400,064	21,331,127
Cash dividends declared per common share:
Cash dividends declared per common share (in usd per share)	$ 0.84	$ 0.81	$ 1.67	$ 1.61