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Restructuring and Impairments - Schedule of Impairment Charges (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Apr. 30, 2019
Apr. 30, 2018
Apr. 30, 2019
Apr. 30, 2018
Oct. 31, 2018
Restructuring Cost and Reserve [Line Items]          
Liability, Defined Benefit Plan, Noncurrent $ (1,950)   $ (1,950)   $ (2,097)
Asset impairment charges $ 1 $ 1 3 $ 3  
Assets Leased to Others [Member]          
Restructuring Cost and Reserve [Line Items]          
Asset impairment charges     $ 3