Retirement and Post-Retirement Benefit Plans - Schedule of Pension and Post-Retirement Benefit (Credit) Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Post-Retirement Benefit Plans
Retirement and post-retirement benefit plans
Service cost	$ 1	$ 0	$ 1	$ 0
Interest cost	2	4	5	8
Expected return on plan assets	(5)	(5)	(11)	(10)
Amortization and deferrals:
Actuarial loss (gain)	(3)	(8)	(5)	(16)
Prior service benefit	(3)	(3)	(6)	(6)
Net periodic (credit) benefit cost	(8)	(12)	(16)	(24)
Settlement loss	0	0	0	0
Special termination benefit cost			44	0
Total periodic benefit (credit) cost	(8)	(12)	28	(24)
U.S. | Defined Benefit Plans
Retirement and post-retirement benefit plans
Service cost	0	0	0	0
Interest cost	103	123	206	246
Expected return on plan assets	(175)	(146)	(350)	(291)
Amortization and deferrals:
Actuarial loss (gain)	16	15	32	30
Prior service benefit	0	0	0	0
Net periodic (credit) benefit cost	(56)	(8)	(112)	(15)
Settlement loss	1	1	1	1
Special termination benefit cost			0	0
Total periodic benefit (credit) cost	(55)	(7)	(111)	(14)
Non-U.S. | Defined Benefit Plans
Retirement and post-retirement benefit plans
Service cost	15	15	31	29
Interest cost	4	6	9	12
Expected return on plan assets	(10)	(9)	(21)	(19)
Amortization and deferrals:
Actuarial loss (gain)	11	8	21	16
Prior service benefit	0	0	(1)	(1)
Net periodic (credit) benefit cost	20	20	39	37
Settlement loss	0	0	0	0
Special termination benefit cost			0	0
Total periodic benefit (credit) cost	$ 20	$ 20	$ 39	$ 37