Retirement Benefit Plans (Details) - Benefit Plans - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 23	$ 21	$ 46	$ 42
Interest cost	35	56	71	111
Expected return on plan assets	(134)	(130)	(269)	(260)
Amortization and deferrals:
Actuarial loss	65	60	129	117
Prior service benefit	(4)	(4)	(7)	(8)
Net periodic benefit (credit) cost	(15)	3	(30)	2
Settlement loss	1	1	1	6
Special termination benefits	1	1	1	1
Net benefit (credit) cost	$ (13)	$ 5	$ (28)	$ 9