Fair Value Measurements - Level 3 Reconciliation (Details) - Guarantees [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Fair Value Assets And Liablities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Beginning Value	$ (19)	$ (7)	$ (10)	$ (8)
Transfers out of Level 3	0	0	0	0
Issuances	(5)	(4)	(16)	(4)
Settlements	1	1	3	2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability) Ending Value	(23)	(10)	(23)	(10)
Change in unrealized gains on assets and liabilities still held	$ 0	$ 0	$ 0	$ 0