EARNINGS PER SHARE - Computation of Earnings Per Share Basic and Diluted (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Numerator for basic and diluted EPS
Net income attributable to Greif, Inc.	$ 11.4	$ 13.6	$ 43.7	$ 43.3
Cash dividends	(26.1)	(26.1)	(52.0)	(51.8)
Undistributed net income attributable to Greif, Inc.	$ (14.7)	$ (12.5)	$ (8.3)	$ (8.5)