Supplementary Financial Information - Other Non-Current Liabilities (Details) - USD ($) $ in Millions	Oct. 31, 2020	Oct. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Pension, post-retirement, and post-employment liabilities	$ 1,576	$ 1,762
Deferred revenue	1,072	1,069
Operating lease liabilities	904
Tax liability	746	848
Deferred tax liability	25	60
Other	823	848
Other non-current liabilities	$ 5,146	$ 4,587