Retirement and Post-Retirement Benefit Plans - Summary of Pre-Tax Net Actuarial Loss (Gain) and Prior Service Benefit Recognized in Accumulated Other Comprehensive Loss for Defined Benefit and Post-Retirement Benefit Plans (Details) $ in Millions	Oct. 31, 2019 USD ($)
Post-Retirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial loss (gain)	$ (135)
Prior service benefit	(94)
Total recognized in Accumulated other comprehensive loss (gain)	(229)
U.S. | Defined Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial loss (gain)	1,371
Prior service benefit	0
Total recognized in Accumulated other comprehensive loss (gain)	1,371
Non-U.S. | Defined Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial loss (gain)	413
Prior service benefit	(12)
Total recognized in Accumulated other comprehensive loss (gain)	$ 401