Supplementary Financial Information - Other Non-Current Liabilities (Details) - USD ($) $ in Millions	Jul. 31, 2018	Oct. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Pension, post-retirement, and post-employment liabilities	$ 1,755	$ 1,999
Deferred tax liability	92	1,410
Tax liability	2,371	2,005
Deferred revenue	981	921
Other	813	827
Other non-current liabilities	$ 6,012	$ 7,162