Supplementary Financial Information - Other Non-Current Liabilities (Details) - USD ($) $ in Millions	Jan. 31, 2019	Oct. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Pension, post-retirement, and post-employment liabilities	$ 1,619	$ 1,645
Deferred tax liability	64	100
Tax liability	1,977	2,063
Deferred revenue	986	1,005
Other	776	793
Other non-current liabilities	$ 5,422	$ 5,606