CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS’ EQUITY (UNAUDITED) - USD ($) shares in Thousands, $ in Millions	Total	Executive	Directors	Capital Stock	Capital Stock Executive	Capital Stock Directors	Treasury Stock	Treasury Stock Executive	Treasury Stock Directors	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Greif, Inc. Equity	Greif, Inc. Equity Executive	Greif, Inc. Equity Directors	Non controlling interests
Beginning balance (shares) at Oct. 31, 2019				48,266			28,576
Beginning balance at Oct. 31, 2019	$ 1,191.1			$ 162.6			$ (134.8)			$ 1,539.0	$ (433.7)	$ 1,133.1			$ 58.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	76.3									64.4		64.4			11.9
Other comprehensive income (loss):
Foreign currency translation	4.2										12.6	12.6			(8.4)
Derivative financial instruments, net of income tax expense	(20.9)										(20.9)	(20.9)
Minimum pension liability adjustment, net of income tax expense	20.6										20.6	20.6
Comprehensive income	80.2											76.7
Current period mark to redemption value of redeemable noncontrolling interest	2.2									2.2		2.2
Net income allocated to redeemable noncontrolling interests	0.2														0.2
Dividends paid to Greif, Inc. shareholders	(78.2)									(78.2)		(78.2)
Dividends paid to noncontrolling interests and other	(12.1)														(12.1)
Long-term incentive shares issued (shares)				153			153
Long-term incentive shares issued	5.3			$ 5.0			$ 0.3					5.3
Share based compensation	1.0			$ 1.0								1.0
Restricted stock (shares)					3	28		(3)	(28)
Restricted stock		$ 0.2	$ 1.0		$ 0.1	$ 1.0		$ 0.1					$ 0.2	$ 1.0
Ending balance (shares) at Jul. 31, 2020				48,450			28,392
Ending balance at Jul. 31, 2020	1,190.9			$ 169.7			$ (134.4)			1,527.4	(421.4)	1,141.3			49.6
Beginning balance (shares) at Apr. 30, 2020				48,450			28,392
Beginning balance at Apr. 30, 2020	1,135.2			$ 169.2			$ (134.4)			1,531.8	(483.4)	1,083.2			52.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24.4									20.7		20.7			3.7
Other comprehensive income (loss):
Foreign currency translation	59.6										62.4	62.4			(2.8)
Derivative financial instruments, net of income tax expense	2.0										2.0	2.0
Minimum pension liability adjustment, net of income tax expense	(2.4)										(2.4)	(2.4)
Comprehensive income	83.6											82.7
Current period mark to redemption value of redeemable noncontrolling interest	1.1									1.1		1.1
Net income allocated to redeemable noncontrolling interests	0.3														0.3
Dividends paid to Greif, Inc. shareholders	(26.2)									(26.2)		(26.2)
Dividends paid to noncontrolling interests and other	(3.6)														(3.6)
Share based compensation	0.5			$ 0.5								0.5
Ending balance (shares) at Jul. 31, 2020				48,450			28,392
Ending balance at Jul. 31, 2020	1,190.9			$ 169.7			$ (134.4)			1,527.4	(421.4)	1,141.3			49.6
Beginning balance (shares) at Oct. 31, 2020				48,450			28,392
Beginning balance at Oct. 31, 2020	1,200.7			$ 170.2			$ (134.4)			1,543.9	(427.5)	1,152.2			48.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	303.3									286.2		286.2			17.1
Other comprehensive income (loss):
Foreign currency translation	18.7										17.9	17.9			0.8
Derivative financial instruments, net of income tax expense	10.8										10.8	10.8
Minimum pension liability adjustment, net of income tax expense	49.3										49.3	49.3
Comprehensive income	382.1											364.2
Current period mark to redemption value of redeemable noncontrolling interest	2.2									2.2		2.2
Net income allocated to redeemable noncontrolling interests	(1.4)														(1.4)
Dividends paid to Greif, Inc. shareholders	(78.4)									(78.4)		(78.4)
Dividends paid to noncontrolling interests and other	(6.4)														(6.4)
Long-term incentive shares issued (shares)				80			80
Long-term incentive shares issued	4.1			$ 3.9			$ 0.2					4.1
Share based compensation	3.2			$ 3.2								3.2
Restricted stock (shares)					3	26		(3)	(26)
Restricted stock		$ 0.1	$ 1.3		$ 0.1	$ 1.2			$ 0.1				$ 0.1	$ 1.3
Ending balance (shares) at Jul. 31, 2021				48,559			28,283
Ending balance at Jul. 31, 2021	1,507.5			$ 178.6			$ (134.1)			1,753.9	(349.5)	1,448.9			58.6
Beginning balance (shares) at Apr. 30, 2021				48,559			28,283
Beginning balance at Apr. 30, 2021	1,429.7			$ 177.6			$ (134.1)			1,666.1	(335.4)	1,374.2			55.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	118.4									113.0		113.0			5.4
Other comprehensive income (loss):
Foreign currency translation	(15.5)										(15.7)	(15.7)			0.2
Derivative financial instruments, net of income tax expense	(0.6)										(0.6)	(0.6)
Minimum pension liability adjustment, net of income tax expense	2.2										2.2	2.2
Comprehensive income	104.5											98.9
Current period mark to redemption value of redeemable noncontrolling interest	1.0									1.0		1.0
Net income allocated to redeemable noncontrolling interests	(0.6)														(0.6)
Dividends paid to Greif, Inc. shareholders	(26.2)									(26.2)		(26.2)
Dividends paid to noncontrolling interests and other	(1.9)														(1.9)
Share based compensation	1.0			$ 1.0								1.0
Ending balance (shares) at Jul. 31, 2021				48,559			28,283
Ending balance at Jul. 31, 2021	$ 1,507.5			$ 178.6			$ (134.1)			$ 1,753.9	$ (349.5)	$ 1,448.9			$ 58.6