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, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Post-Retirement Benefit Plans
Retirement and post-retirement benefit plans
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	4	4	8	8
Expected return on plan assets	(5)	(6)	(10)	(12)
Amortization and deferrals:
Actuarial loss (gain)	(8)	(4)	(16)	(8)
Prior service benefit	(3)	(5)	(6)	(10)
Net periodic (credit) benefit cost	(12)	(11)	(24)	(22)
Settlement loss	0	0	0	0
Total periodic benefit (credit) cost	(12)	(11)	(24)	(22)
U.S. | Defined Benefit Plans
Retirement and post-retirement benefit plans
Service cost	0	0	0	0
Interest cost	123	113	246	226
Expected return on plan assets	(146)	(179)	(291)	(360)
Amortization and deferrals:
Actuarial loss (gain)	15	16	30	31
Prior service benefit	0	0	0	0
Net periodic (credit) benefit cost	(8)	(50)	(15)	(103)
Settlement loss	1	0	1	1
Total periodic benefit (credit) cost	(7)	(50)	(14)	(102)
Non-U.S. | Defined Benefit Plans
Retirement and post-retirement benefit plans
Service cost	15	14	29	28
Interest cost	6	6	12	12
Expected return on plan assets	(9)	(10)	(19)	(20)
Amortization and deferrals:
Actuarial loss (gain)	8	7	16	14
Prior service benefit	0	(1)	(1)	(2)
Net periodic (credit) benefit cost	20	16	37	32
Settlement loss	0	0	0	0
Total periodic benefit (credit) cost	$ 20	$ 16	$ 37	$ 32