Restructuring and Impairments - Restructuring Reserve by Type (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Oct. 31, 2015	Oct. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 3	$ 3
Restructuring Reserve	45	17	$ 68	$ 20
Restructuring and Related Cost, Incurred Cost	4	3
Payments for Restructuring	25	5
Restructuring Reserve, Accrual Adjustment	(2)	(1)
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	42	7	62	8
Restructuring and Related Cost, Incurred Cost	4	3
Payments for Restructuring	22	3
Restructuring Reserve, Accrual Adjustment	(2)	(1)
Lease Vacancy [Member] [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	2	9	5	11
Restructuring and Related Cost, Incurred Cost	0	0
Payments for Restructuring	3	2
Restructuring Reserve, Accrual Adjustment	0	0
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	1	1	$ 1	$ 1
Restructuring and Related Cost, Incurred Cost	0	0
Payments for Restructuring	0	0
Restructuring Reserve, Accrual Adjustment	$ 0	$ 0