Consolidated Statements of Changes in Shareholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Executive Officer [Member]	Director [Member]	Capital Stock	Capital Stock Executive Officer [Member]	Capital Stock Director [Member]	Treasury Stock	Treasury Stock Executive Officer [Member]	Treasury Stock Director [Member]	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss)	Greif, Inc. Equity	Greif, Inc. Equity Executive Officer [Member]	Greif, Inc. Equity Director [Member]	Greif, Inc. Equity Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interests
Beginning balance (shares) at Oct. 31, 2017				47,843			28,999
Beginning balance, value at Oct. 31, 2017	$ 1,047.5			$ 144.2			$ (135.6)			$ 1,360.5		$ (358.2)	$ 1,010.9				$ 36.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	229.5									209.4			209.4				20.1
Other comprehensive income (loss):
Foreign currency translation	(45.5)											(43.5)	(43.5)				(2.0)
Derivative financial instruments, net of income tax expense (benefit)	7.7									(0.6)		8.3	7.7
Minimum pension liability adjustment, net of income tax expense	16.3											16.3	16.3
Comprehensive income	208.0												189.9
Current period mark to redemption value of redeemable noncontrolling interest	0.5									0.5			0.5
Net income allocated to redeemable noncontrolling interests	(3.7)																(3.7)
Dividends paid	(100.0)									(100.0)			(100.0)
Dividends paid to noncontrolling interests	(4.6)																(4.6)
Restricted stock executives and directors (shares)				21			(21)
Restricted stock directors	1.2			$ 1.2			$ 0.0						1.2
Long-term incentive shares issued (shares)				85			(85)
Long-term incentive shares issued	5.3			$ 5.1			$ 0.2						5.3
Ending balance (shares) at Oct. 31, 2018				47,949			28,893
Ending balance, value at Oct. 31, 2018	1,154.2			$ 150.5			$ (135.4)			1,469.8	$ (2.1)	(377.1)	1,107.8			$ (2.1)	46.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	194.2									171.0			171.0				23.2
Other comprehensive income (loss):
Foreign currency translation	(4.5)											(5.2)	(5.2)				0.7
Derivative financial instruments, net of income tax expense (benefit)	(26.1)											(26.1)	(26.1)
Minimum pension liability adjustment, net of income tax expense	(25.3)											(25.3)	(25.3)
Comprehensive income	138.3												114.4
Current period mark to redemption value of redeemable noncontrolling interest	4.9									4.9			4.9
Net income allocated to redeemable noncontrolling interests	(2.3)																(2.3)
Dividends paid	(104.0)									(104.0)			(104.0)
Dividends paid to noncontrolling interests	(7.9)																(7.9)
Acquisition of noncontrolling interest and other	(2.7)									(0.6)			(0.6)				(2.1)
Restricted stock executives and directors (shares)				25			(25)
Restricted stock directors	1.1			$ 1.1			$ 0.0						1.1
Long-term incentive shares issued (shares)				292			(292)
Long-term incentive shares issued	11.6			$ 11.0			$ 0.6						11.6
Ending balance (shares) at Oct. 31, 2019				48,266			28,576
Ending balance, value at Oct. 31, 2019	$ 1,191.1			$ 162.6			$ (134.8)			1,539.0		(433.7)	1,133.1				58.0
Other comprehensive income (loss):
Adoption of ASU 2016-16	gef:Accountingstandardsupdate201616_1
Net income	$ 124.3									108.8			108.8				15.5
Foreign currency translation	(9.8)											3.1	3.1				(12.9)
Derivative financial instruments, net of income tax expense (benefit)	(12.0)											(12.0)	(12.0)
Minimum pension liability adjustment, net of income tax expense	15.1											15.1	15.1
Comprehensive income	117.6												115.0
Current period mark to redemption value of redeemable noncontrolling interest	0.4									0.4			0.4
Net income allocated to redeemable noncontrolling interests	(0.1)																(0.1)
Dividends paid	(104.3)									(104.3)			(104.3)
Dividends paid to noncontrolling interests	(12.0)																(12.0)
Long-term incentive shares issued	5.3												5.3
Restricted stock executives and directors (shares)					3	28		(3)	(28)
Restricted stock directors		$ 0.1	$ 1.1		$ 0.1	$ 1.0		$ 0.0	$ 0.1					$ 0.1	$ 1.1
Long-term incentive shares issued (shares)				153			(153)
Long-term incentive shares issued				$ 5.0			$ 0.3
Share based compensation	1.5			$ 1.5									1.5
Ending balance (shares) at Oct. 31, 2020				48,450			28,392
Ending balance, value at Oct. 31, 2020	$ 1,200.7			$ 170.2			$ (134.4)			$ 1,543.9		$ (427.5)	$ 1,152.2				$ 48.5