Supplementary Financial Information - Other Non-Current Liabilities (Details) - USD ($) $ in Millions	Apr. 30, 2018	Oct. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Pension, post-retirement, and post-employment liabilities	$ 1,843	$ 1,999
Deferred tax liability	86	1,410
Tax liability	2,577	2,005
Deferred revenue	956	921
Other	867	827
Other non-current liabilities	$ 6,329	$ 7,162