Restructuring and Impairments - Restructuring Reserve by Type (Details) - USD ($) $ in Millions	3 Months Ended						6 Months Ended
	Apr. 30, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Jul. 31, 2014	Apr. 30, 2018	Apr. 30, 2017	Oct. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1	$ 6	$ 41	$ 2			$ (2)	$ 9
Restructuring Reserve	8	15		10			8	10	$ 7
Restructuring and Related Cost, Incurred Cost							1	8
Payments for Restructuring							(5)	(4)
Restructuring Reserve, Accrual Adjustment							(3)	(1)
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	7	14		9			7	9	5
Restructuring and Related Cost, Incurred Cost							1	8
Payments for Restructuring							(5)	(3)
Restructuring Reserve, Accrual Adjustment							(3)	(1)
Lease Vacancy [Member] [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0	0		0			0	0	1
Restructuring and Related Cost, Incurred Cost							0	0
Payments for Restructuring							0	(1)
Restructuring Reserve, Accrual Adjustment							0	0
Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 1	$ 1		$ 1			1	1	$ 1
Restructuring and Related Cost, Incurred Cost							0	0
Payments for Restructuring							0	0
Restructuring Reserve, Accrual Adjustment							$ 0	$ 0
Other Postretirement Benefits Plan [Member] | Chatham [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Postemployment Benefits, Period Expense			$ 23		$ 6	$ 14